Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Cash flows from operating activities:
Net income	$ 50,365	$ 31,815	$ 46,848
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	20,678	20,512	16,094
Bad debt expense	2,257	1,109	1,195
(Gain) loss on sale or disposition of assets and sublease, net	(139)	4,260	(171)
Loss on early extinguishment of debt			796
Equity-based compensation expense	9,176	2,900	2,330
Deferred income tax expense	9,552	47,965	3,367
Fair value adjustments to contingent consideration	(1,289)	180	100
Payments pursuant to tax receivable agreements	(6,305)	(13,371)	(1,344)
Non-cash change in tax receivable agreement liability	(6,145)	(32,736)
Other	1,082	1,145	1,029
Changes in operating assets and liabilities:
Accounts and notes receivable, current portion	(3,241)	(2,825)	(3,841)
Advances from/to affiliates	581	(106)	71
Other current and noncurrent assets	2,170	(2,724)	186
Other current and noncurrent liabilities	(3,497)	2,815	(1,956)
Income taxes receivable/payable	560	(1,133)	(71)
Deferred revenue and deposits, current portion	259	3,482	(254)
Net cash provided by operating activities	76,064	63,288	64,379
Cash flows from investing activities:
Purchases of property, equipment and software and capitalization of trademark costs	(7,787)	(2,198)	(4,502)
Acquisitions, net of cash acquired of $362, $0 and $131, respectively	(25,888)	(35,720)	(112,934)
Dispositions			200
Other investing activity, net			(96)
Net cash (used in) provided by investing activities	(33,675)	(37,918)	(117,332)
Cash flows from financing activities:
Proceeds from issuance of debt			233,825
Payments on debt	(3,171)	(2,366)	(203,298)
Capitalized debt amendment costs			(1,379)
Distributions paid to non-controlling unitholders	(14,559)	(17,260)	(17,927)
Dividends and dividend equivalents paid to Class A common stockholders	(14,306)	(12,793)	(10,578)
Proceeds from exercise of stock options			101
Payment of payroll taxes related to net settled restricted stock units	(895)	(816)	(516)
Payment of contingent consideration	(221)
Net cash (used in) provided by financing activities	(33,152)	(33,235)	228
Effect of exchange rate changes on cash	(70)	1,063	122
Net increase (decrease) in cash and cash equivalents	9,167	(6,802)	(52,603)
Cash and cash equivalents, beginning of year	50,807	57,609	110,212
Cash and cash equivalents, end of period	59,974	50,807	57,609
Supplemental disclosures of cash flow information:
Cash paid for interest	11,525	9,972	7,797
Net cash paid for income taxes	5,769	10,078	11,912
Schedule of non-cash investing and financing activities:
Note receivable received as consideration for sale of brokerage operations assets			150
Increase in accounts payable for capitalization of trademark costs and purchases of property, equipment and software	$ 1,080	$ 295	150
Contingent consideration issued in a business acquisition			$ 6,300