Acquisitions (Details) - USD ($) $ / shares in Units, $ in Thousands					12 Months Ended
	Sep. 10, 2020	Aug. 25, 2020	Dec. 16, 2019	Feb. 26, 2018	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Jan. 01, 2019
Business Acquisition [Line Items]
Cash consideration, net of cash acquired					$ 10,627	$ 14,945	$ 25,888
Purchase Price Allocation
Goodwill					$ 175,835	$ 159,038	150,684
Pro Forma Information
Total revenue							287,394
Net income attributable to Holdings							$ 26,131
Basic earnings per common share							$ 1.47
Diluted earnings per common share							$ 1.47
First Leads
Business Acquisition [Line Items]
Cash consideration			$ 15,000
Gadberry
Business Acquisition [Line Items]
Cash consideration, net of cash acquired	$ 4,600
Maximum amount of equity based compensation to be earned over time	9,900
Equity-based compensation, value	$ 900
Gadberry | Minimum
Business Acquisition [Line Items]
Period over which equity based compensation will be accounted for into the future (in years)	2 years
Gadberry | Maximum
Business Acquisition [Line Items]
Period over which equity based compensation will be accounted for into the future (in years)	3 years
Gadberry | Common Class A
Business Acquisition [Line Items]
Consideration transferred, stock	$ 5,500
Wemlo
Business Acquisition [Line Items]
Cash consideration, net of cash acquired		$ 6,100
Maximum amount of equity based compensation to be earned over time		$ 6,700
Period over which equity based compensation will be accounted for into the future (in years)		3 years
Purchase Price Allocation
Other intangible assets		$ 6,300
Goodwill		14,400
Wemlo | Common Class A
Business Acquisition [Line Items]
Consideration transferred, stock		$ 3,300
Marketing funds
Purchase Price Allocation
Restricted cash								$ 28,495
Other current assets								8,472
Property and equipment								788
Other assets, net of current portion								126
Total assets acquired								37,881
Other current liabilities								(37,881)
Total liabilities assumed								$ (37,881)
Booj Llc
Business Acquisition [Line Items]
Cash consideration				$ 26,300
Maximum amount of equity based compensation to be earned over time				10,000
Purchase Price Allocation
Cash				362
Other current assets				367
Property and equipment				625
Software				7,400
Trademarks				500
Non-compete agreement				1,200
Customer relationships				800
Other intangible assets				1,589
Other assets, net of current portion				336
Total assets acquired, excluding goodwill				13,179
Current portion of debt				(606)
Other current liabilities				(557)
Debt, net of current portion				(805)
Total liabilities assumed				(1,968)
Goodwill				15,039
Total acquisition price				$ 26,250