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

Income Taxes - Additional Information (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended	0 Months Ended	3 Months Ended	9 Months Ended
	Sep. 30, 2014	Jun. 30, 2014	Sep. 30, 2014	Oct. 31, 2013 Tax-sharing agreement [Member]	Sep. 30, 2013 Tax-sharing agreement [Member]	Sep. 30, 2014 Tax-sharing agreement [Member]	Sep. 30, 2013 Tax-sharing agreement [Member]	Sep. 30, 2014 Estimated 2014 annual effective tax rate [Member]
Income Taxes [Line Items]
Effective tax rate	41.20%		41.20%	43.50%	43.50%		43.50%	40.90%
Tax benefit of deductible IPO transaction costs		$ 840	$ 840
Tax-sharing agreement termination date						Oct. 31, 2013