Segment information (Details 2) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Segment Reporting Information [Line Items]
Net income	$ 15,193	$ 14,055	$ 40,381	$ 36,362
Depreciation and amortization	3,765	3,767	11,384	11,517
Interest expense	2,338	2,255	7,448	7,007
Interest income	(36)	(58)	(136)	(205)
Provision for income taxes	3,277	3,116	8,882	8,130
EBITDA	24,537	23,135	67,959	62,811
(Gain) loss on sale or disposition of assets and sublease	(66)	(52)	(773)	(277)
Loss on early extinguishment of debt			94	178
Non-cash straight-line rent expense	201	197	681	614
Non-recurring severance and other related expenses	443		1,482
Acquisition integration and professional fees expense		87	77	150
Adjusted EBITDA	25,115	23,367	69,520	63,476
Real Estate Franchise Services
Segment Reporting Information [Line Items]
Net income	14,682	13,459	38,576	36,017
Depreciation and amortization	3,694	3,695	11,159	11,305
Interest expense	2,328	2,252	7,413	6,997
Interest income	(36)	(58)	(136)	(205)
Provision for income taxes	3,182	3,014	8,553	8,070
EBITDA	23,850	22,362	65,565	62,184
(Gain) loss on sale or disposition of assets and sublease	(88)	(87)	(259)	(369)
Loss on early extinguishment of debt			94	178
Non-cash straight-line rent expense	224	271	736	773
Non-recurring severance and other related expenses	443		1,482
Acquisition integration and professional fees expense		87	77	150
Adjusted EBITDA	24,429	22,633	67,695	62,916
Brokerages
Segment Reporting Information [Line Items]
Net income	511	596	1,805	345
Depreciation and amortization	71	72	225	212
Interest expense	10	3	35	10
Provision for income taxes	95	102	329	60
EBITDA	687	773	2,394	627
(Gain) loss on sale or disposition of assets and sublease	22	35	(514)	92
Non-cash straight-line rent expense	(23)	(74)	(55)	(159)
Adjusted EBITDA	$ 686	$ 734	$ 1,825	$ 560