Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Cash flows from operating activities:
Net income	$ 46,856	$ 49,822	$ 31,320
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	22,323	20,678	20,512
Bad debt expense	4,964	2,257	1,109
Loss (gain) on sale or disposition of assets and sublease, net	342	(139)	4,260
Equity-based compensation expense	10,934	9,176	2,900
Deferred income tax expense	2,310	9,511	47,931
Fair value adjustments to contingent consideration	241	(1,289)	180
Payments pursuant to tax receivable agreements	(3,556)	(6,305)	(13,371)
Non-cash change in tax receivable agreement liability	0	(6,145)	(32,736)
Other, net	910	1,127	1,146
Changes in operating assets and liabilities
Accounts and notes receivable, current portion	(5,614)	(3,241)	(2,825)
Advances from/to affiliates	0	581	(106)
Other current and noncurrent assets	(6,084)	2,170	(2,724)
Other current and noncurrent liabilities	6,737	(3,466)	1,592
Income taxes receivable/payable	178	1,099	(605)
Deferred revenue, current and noncurrent	(1,566)	228	4,705
Net cash provided by operating activities	78,975	76,064	63,288
Cash flows from investing activities:
Purchases of property, equipment and capitalization of software	(13,226)	(7,787)	(2,198)
Acquisitions, net of cash acquired of $55, $362 and $0, respectively	(14,945)	(25,888)	(35,720)
Restricted cash acquired with the Marketing Funds acquisition	28,495	0	0
Other	(1,200)	0	0
Net cash used in investing activities	(876)	(33,675)	(37,918)
Cash flows from financing activities:
Payments on debt	(2,622)	(3,171)	(2,366)
Distributions paid to non-controlling unitholders	(15,430)	(14,559)	(17,260)
Dividends and dividend equivalents paid to Class A common stockholders	(15,074)	(14,306)	(12,793)
Payment of payroll taxes related to net settled restricted stock units	(1,110)	(895)	(816)
Payment of contingent consideration	(306)	(221)
Net cash used in financing activities	(34,542)	(33,152)	(33,235)
Effect of exchange rate changes on cash	70	(70)	1,063
Net increase (decrease) in cash, cash equivalents and restricted cash	43,627	9,167	(6,802)
Cash, cash equivalents and restricted cash, beginning of year	59,974	50,807	57,609
Cash, cash equivalents and restricted cash, end of period	103,601	59,974	50,807
Supplemental disclosures of cash flow information:
Cash paid for interest	11,690	11,525	9,972
Net cash paid for income taxes	8,429	5,769	10,078
Schedule of non-cash investing activities:
Increase (decrease) in accounts payable and accrued liabilities for purchases of property, equipment and capitalization of software	$ (94)	$ 1,080	$ 295