CONDENSED CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) shares in Thousands, $ in Thousands	Total	Additional Paid-In Capital	Retained Earnings	Accumulated Other Comprehensive Income (Loss)	Non-controlling Interest	Class A Common Stock Common stock	Class B Common Stock Common stock
Balance at the beginning of the period (in shares) at Dec. 31, 2019						47,159	27,958
Balance at the beginning of the period at Dec. 31, 2019	$ 516,395	$ 194,456	$ 132,990	$ (452)	$ 188,929	$ 472	$ 0
Statement of Stockholders'/Members' Equity
Member distributions	(4,712)				(4,712)
Effect of CW Unit redemptions (in shares)						74	(74)
Effect of CW Unit redemptions	0	539			(540)	$ 1
Tax impact of equity transactions	62	62
Equity award vestings (in shares)						245
Equity award vestings	(1,386)	(218)			(1,170)	$ 2
Other comprehensive loss (income)	(204)			(117)	(87)
Stock-based compensation	4,204	2,645			1,559
Cash dividends declared	(8,645)		(8,645)
Net income	42,193		25,011		17,182
Balance at the end of the period (in shares) at Jun. 30, 2020						47,478	27,884
Balance at the end of the period at Jun. 30, 2020	547,907	197,484	149,356	(569)	201,161	$ 475	$ 0
Balance at the beginning of the period (in shares) at Mar. 31, 2020						47,398	27,958
Balance at the beginning of the period at Mar. 31, 2020	542,426	195,381	147,670	(1,067)	199,968	$ 474	$ 0
Statement of Stockholders'/Members' Equity
Member distributions	(2,509)				(2,509)
Effect of CW Unit redemptions (in shares)						74	(74)
Effect of CW Unit redemptions	0	539			(540)	$ 1
Tax impact of equity transactions	156	156
Equity award vestings (in shares)						6
Equity award vestings	(29)	3			(32)
Other comprehensive loss (income)	879			498	381
Stock-based compensation	2,231	1,405			826
Cash dividends declared	(4,342)		(4,342)
Net income	9,095		6,028		3,067
Balance at the end of the period (in shares) at Jun. 30, 2020						47,478	27,884
Balance at the end of the period at Jun. 30, 2020	547,907	197,484	149,356	(569)	201,161	$ 475	$ 0
Balance at the beginning of the period (in shares) at Dec. 31, 2020						47,713	27,655
Balance at the beginning of the period at Dec. 31, 2020	550,770	202,077	150,086	330	197,800	$ 477	$ 0
Balance at the end of the period (in shares) at Mar. 31, 2021						54,317	21,383
Balance at the end of the period at Mar. 31, 2021	559,050	247,875	157,286	255	153,091	$ 543	$ 0
Balance at the beginning of the period (in shares) at Dec. 31, 2020						47,713	27,655
Balance at the beginning of the period at Dec. 31, 2020	550,770	202,077	150,086	330	197,800	$ 477	$ 0
Statement of Stockholders'/Members' Equity
Member distributions	(3,560)				(3,560)
Effect of CW Unit redemptions (in shares)						9,990	(9,990)
Effect of CW Unit redemptions	0	71,911			(72,011)	$ 100
Tax impact of equity transactions	2,436	2,436
Equity award vestings (in shares)						335
Equity award vestings	(3,174)	(1,067)			(2,110)	$ 3
Other comprehensive loss (income)	(275)			(113)	(162)
Stock-based compensation	4,438	3,148			1,290
Cash dividends declared	(9,370)		(9,370)
Net income	29,910		21,952		7,958
Balance at the end of the period (in shares) at Jun. 30, 2021						58,038	17,665
Balance at the end of the period at Jun. 30, 2021	571,175	278,505	162,668	217	129,205	$ 580	$ 0
Balance at the beginning of the period (in shares) at Mar. 31, 2021						54,317	21,383
Balance at the beginning of the period at Mar. 31, 2021	559,050	247,875	157,286	255	153,091	$ 543	$ 0
Statement of Stockholders'/Members' Equity
Member distributions	(1,886)				(1,886)
Effect of CW Unit redemptions (in shares)						3,718	(3,718)
Effect of CW Unit redemptions	0	26,912			(26,949)	$ 37
Tax impact of equity transactions	1,931	1,931
Equity award vestings (in shares)						3
Equity award vestings	(36)	(19)			(17)
Other comprehensive loss (income)	(82)			(38)	(44)
Stock-based compensation	2,435	1,806			629
Cash dividends declared	(5,011)		(5,011)
Net income	14,774		10,393		4,381
Balance at the end of the period (in shares) at Jun. 30, 2021						58,038	17,665
Balance at the end of the period at Jun. 30, 2021	$ 571,175	$ 278,505	$ 162,668	$ 217	$ 129,205	$ 580	$ 0