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

Quarterly report pursuant to Section 13 or 15(d)

Cover
- Cover Page
Financial Statements
Notes to Financial Statements
Accounting Policies
- Description of Business and Basis of Presentation (Policies)
Notes Tables
Notes Details

Investments in Marketable Securities - Additional Information (Detail)

v3.20.2

Investments in Marketable Securities - Additional Information (Detail)	9 Months Ended	12 Months Ended
	Sep. 30, 2020 USD ($)	Dec. 31, 2019 USD ($)
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale, securities in unrealized loss positions, accumulated loss	$ 97,000	$ 22,000
Allowance for credit losses	$ 0
Weighted average contractual maturity	1 year 8 months 12 days	1 year 8 months 12 days
Fitch, AA Rating [Member] \| Moody's, Aaa Rating [Member] \| Standard & Poor's, AA Rating [Member]
Schedule of Available-for-sale Securities [Line Items]
Weighted average contractual maturity	1 year 8 months 12 days
Fitch, AA- Rating [Member] \| Moody's, Aa3 Rating [Member] \| Standard & Poor's, AA- Rating [Member] \| Weighted Average Credit AA- Rating [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale, securities number of unrealized loss positions	20
Available-for-sale, securities in unrealized loss positions, accumulated loss	$ 97,000
Percentage of amortized cost	1.00%

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