Marcus & Millichap, Inc. Annual report pursuant to Section 13 and 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	Dec. 31, 2014	Dec. 31, 2013
Fair Value Assets And Liabilities Measured On Recurring Basis Financial Statement Captions [Line Items]
Investments held in rabbi trust	$ 4,332us-gaap_DeferredCompensationPlanAssets	$ 4,067us-gaap_DeferredCompensationPlanAssets
Marketable securities, available for sale	14,752
Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Financial Statement Captions [Line Items]
Investments held in rabbi trust	4,332
Cash equivalents	25,310
Marketable securities, available for sale	14,752
Recurring [Member] \| Cash Equivalents [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Financial Statement Captions [Line Items]
Cash equivalents	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	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	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	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	2,277
Level 1 [Member] \| Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Financial Statement Captions [Line Items]
Cash equivalents	25,310
Marketable securities, available for sale	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	25,310
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	2,980
Level 2 [Member] \| Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis Financial Statement Captions [Line Items]
Investments held in rabbi trust	4,332
Marketable securities, available for sale	11,772
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	4,332	4,100
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	2,017
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	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	$ 2,277