Segment information - Segment Adjusted EBITDA to Net Income (Detail) (USD $)	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013	Dec. 31, 2013
Segment Reporting Information [Line Items]
Net income	$ 14,055,000	$ 7,697,000	$ 36,362,000	$ 22,652,000
Depreciation and amortization	3,767,000	3,656,000	11,517,000	11,088,000
Interest expense	2,255,000	5,128,000	7,007,000	12,053,000
Interest income	(58,000)	(82,000)	(205,000)	(224,000)
Provision for income taxes	3,116,000	702,000	8,130,000	1,733,000
EBITDA	23,135,000	17,101,000	62,811,000	47,302,000
Loss (gain) on sale or disposition of assets and sublease	(52,000)	(164,000)	(277,000)	(411,000)
Loss on early extinguishment of debt		1,664,000	178,000	1,798,000	1,664,000
Non-recurring equity-based compensation				701,000
Non-cash straight-line rent expense	197,000	261,000	614,000	970,000
Chairman executive compensation		750,000		2,250,000
Acquisition integration costs	87,000	27,000	150,000	249,000
Public offering related expenses		2,436,000		5,916,000
Adjusted EBITDA	23,367,000	22,075,000	63,476,000	58,775,000
Operating Segments | Real Estate Franchise Services
Segment Reporting Information [Line Items]
Net income	13,459,000	6,754,000	36,017,000	20,968,000
Depreciation and amortization	3,695,000	3,571,000	11,305,000	10,792,000
Interest expense	2,252,000	5,128,000	6,997,000	12,050,000
Interest income	(58,000)	(82,000)	(205,000)	(224,000)
Provision for income taxes	3,014,000	702,000	8,070,000	1,733,000
EBITDA	22,362,000	16,073,000	62,184,000	45,319,000
Loss (gain) on sale or disposition of assets and sublease	(87,000)	(94,000)	(369,000)	(266,000)
Loss on early extinguishment of debt		1,664,000	178,000	1,798,000
Non-recurring equity-based compensation				701,000
Non-cash straight-line rent expense	271,000	321,000	773,000	1,031,000
Chairman executive compensation		750,000		2,250,000
Acquisition integration costs	87,000	27,000	150,000	249,000
Public offering related expenses		2,436,000		5,916,000
Adjusted EBITDA	22,633,000	21,177,000	62,916,000	56,998,000
Operating Segments | Brokerage
Segment Reporting Information [Line Items]
Net income	596,000	943,000	345,000	1,684,000
Depreciation and amortization	72,000	85,000	212,000	296,000
Interest expense	3,000		10,000	3,000
Interest income	0	0	0	0
Provision for income taxes	102,000		60,000
EBITDA	773,000	1,028,000	627,000	1,983,000
Loss (gain) on sale or disposition of assets and sublease	35,000	(70,000)	92,000	(145,000)
Non-cash straight-line rent expense	(74,000)	(60,000)	(159,000)	(61,000)
Adjusted EBITDA	$ 734,000	$ 898,000	$ 560,000	$ 1,777,000