Marcus & Millichap, Inc. Quarterly report pursuant to Section 13 or 15(d)

Quarterly report pursuant to Section 13 or 15(d)

Fair Value Measurements - Schedule of Investments at Fair Value on Recurring Basis (Detail)

Fair Value Measurements - Schedule of Investments at Fair Value on Recurring Basis (Detail) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2015	Dec. 31, 2014
Fair Value Assets And Liabilities Measured On Recurring Basis Financial Statement Captions [Line Items]
Investments held in rabbi trust	$ 5,631us-gaap_DeferredCompensationPlanAssets	$ 4,332us-gaap_DeferredCompensationPlanAssets
Marketable securities, available for sale	25,331	14,752
Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Financial Statement Captions [Line Items]
Marketable securities, available for sale	25,331	14,752
Recurring [Member] \| Cash Equivalents [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Financial Statement Captions [Line Items]
Cash equivalents	85,248	25,310
Recurring [Member] \| Investments held in rabbi trust [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Financial Statement Captions [Line Items]
Investments held in rabbi trust	5,631	4,332
Recurring [Member] \| U.S. government and agency debt securities [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Financial Statement Captions [Line Items]
Marketable securities, available for sale	7,093	4,997
Recurring [Member] \| Corporate debt securities [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Financial Statement Captions [Line Items]
Marketable securities, available for sale	14,187	7,478
Recurring [Member] \| Asset-backed securities [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Financial Statement Captions [Line Items]
Marketable securities, available for sale	4,051	2,277
Level 1 [Member] \| Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Financial Statement Captions [Line Items]
Marketable securities, available for sale	5,068	2,980
Level 1 [Member] \| Recurring [Member] \| Cash Equivalents [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Financial Statement Captions [Line Items]
Cash equivalents	85,248	25,310
Level 1 [Member] \| Recurring [Member] \| Investments held in rabbi trust [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Financial Statement Captions [Line Items]
Investments held in rabbi trust	0	0
Level 1 [Member] \| Recurring [Member] \| U.S. government and agency debt securities [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Financial Statement Captions [Line Items]
Marketable securities, available for sale	5,068	2,980
Level 1 [Member] \| Recurring [Member] \| Corporate debt securities [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Financial Statement Captions [Line Items]
Marketable securities, available for sale	0	0
Level 1 [Member] \| Recurring [Member] \| Asset-backed securities [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Financial Statement Captions [Line Items]
Marketable securities, available for sale	0	0
Level 2 [Member] \| Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Financial Statement Captions [Line Items]
Marketable securities, available for sale	20,263	11,772
Level 2 [Member] \| Recurring [Member] \| Cash Equivalents [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Financial Statement Captions [Line Items]
Cash equivalents	0	0
Level 2 [Member] \| Recurring [Member] \| Investments held in rabbi trust [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Financial Statement Captions [Line Items]
Investments held in rabbi trust	5,631	4,332
Level 2 [Member] \| Recurring [Member] \| U.S. government and agency debt securities [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Financial Statement Captions [Line Items]
Marketable securities, available for sale	2,025	2,017
Level 2 [Member] \| Recurring [Member] \| Corporate debt securities [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Financial Statement Captions [Line Items]
Marketable securities, available for sale	14,187	7,478
Level 2 [Member] \| Recurring [Member] \| Asset-backed securities [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Financial Statement Captions [Line Items]
Marketable securities, available for sale	4,051	2,277
Level 3 [Member] \| Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Financial Statement Captions [Line Items]
Marketable securities, available for sale	0	0
Level 3 [Member] \| Recurring [Member] \| Cash Equivalents [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Financial Statement Captions [Line Items]
Cash equivalents	0	0
Level 3 [Member] \| Recurring [Member] \| Investments held in rabbi trust [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Financial Statement Captions [Line Items]
Investments held in rabbi trust	0	0
Level 3 [Member] \| Recurring [Member] \| U.S. government and agency debt securities [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Financial Statement Captions [Line Items]
Marketable securities, available for sale	0	0
Level 3 [Member] \| Recurring [Member] \| Corporate debt securities [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Financial Statement Captions [Line Items]
Marketable securities, available for sale	0	0
Level 3 [Member] \| Recurring [Member] \| Asset-backed securities [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Financial Statement Captions [Line Items]
Marketable securities, available for sale	$ 0	$ 0