Marcus & Millichap, Inc. Annual report pursuant to Section 13 and 15(d)

Selected Balance Sheet Data - Schedule of Other Assets (Parenthetical) (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Other Assets [Line Items]
Weighted average interest rate for notes receivable	3.50%	3.30%
Allowance of doubtful accounts	$ 494	$ 313
Provision for bad debt expense	219	47	$ 281
Write-off receivables	$ 38	$ 93	$ 115
Minimum [Member]
Other Assets [Line Items]
Notes receivable due period	1 year
Maximum [Member]
Other Assets [Line Items]
Notes receivable due period	5 years