CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) $ in Thousands	Common Stock	Additional Paid-in Capital	Retained Earnings	Accumulated Other Comprehensive Income (Loss)	Non Controlling Interest	Total
Balance at Dec. 31, 2018	$ 5	$ 144,048	$ 461,075	$ (908)	$ 2,763	$ 606,983
Balance (in shares) at Dec. 31, 2018	50,715,518
Increase (Decrease) in Stockholders' Equity Roll Forward
Net income			19,734		1,026	20,760
Foreign currency translation adjustments, net of tax				736		736
Issuance of shares to employees and/or directors		2,661				2,661
Issuance of shares to employees and/or directors (in shares)	127,384
Conversion of Restricted Stock Units, net of shares withheld for taxes		(1,519)				$ (1,519)
Conversion of Restricted Stock Units, net of shares withheld for taxes (in shares)	122,319					122,319
Amortization of Restricted Stock Units		858				$ 858
Dividend equivalent Units accrued - Restricted Stock Units		16	(16)
Distribution of noncontrolling entities					(3,505)	(3,505)
Dividends declared			(6,109)			(6,109)
Balance at Jun. 30, 2019	$ 5	146,064	474,684	(172)	284	620,865
Balance (in shares) at Jun. 30, 2019	50,965,221
Balance at Mar. 31, 2019	$ 5	147,208	459,959	(534)	3,747	610,385
Balance (in shares) at Mar. 31, 2019	50,842,902
Increase (Decrease) in Stockholders' Equity Roll Forward
Net income			17,787		37	17,824
Foreign currency translation adjustments, net of tax				362		362
Conversion of Restricted Stock Units, net of shares withheld for taxes		(1,519)				$ (1,519)
Conversion of Restricted Stock Units, net of shares withheld for taxes (in shares)	122,319					122,319
Amortization of Restricted Stock Units		371				$ 371
Dividend equivalent Units accrued - Restricted Stock Units		4	(4)
Distribution of noncontrolling entities					(3,500)	(3,500)
Dividends declared			(3,058)			(3,058)
Balance at Jun. 30, 2019	$ 5	146,064	474,684	(172)	284	620,865
Balance (in shares) at Jun. 30, 2019	50,965,221
Balance at Dec. 31, 2019	$ 5	97,130	531,291	76	1,028	629,530
Balance (in shares) at Dec. 31, 2019	48,665,138
Increase (Decrease) in Stockholders' Equity Roll Forward
Net income			29,222		6	29,228
Foreign currency translation adjustments, net of tax				(1,185)		(1,185)
Issuance of shares to employees and/or directors		1,337				1,337
Issuance of shares to employees and/or directors (in shares)	61,719
Conversion of Restricted Stock Units, net of shares withheld for taxes		(77)				$ (77)
Conversion of Restricted Stock Units, net of shares withheld for taxes (in shares)	13,516					13,516
Amortization of Restricted Stock Units		1,202				$ 1,202
Dividend equivalent Units accrued - Restricted Stock Units		8	(8)
Repurchase of stock		(8,343)				(8,343)
Repurchase of stock (in shares)	(519,562)
Distribution of noncontrolling entities					(1,000)	(1,000)
Dividends declared			(5,788)			(5,788)
Balance at Jun. 30, 2020	$ 5	91,257	554,717	(1,109)	34	644,904
Balance (in shares) at Jun. 30, 2020	48,220,811
Balance at Mar. 31, 2020	$ 5	91,414	524,655	(1,661)	1,031	615,444
Balance (in shares) at Mar. 31, 2020	48,254,575
Increase (Decrease) in Stockholders' Equity Roll Forward
Net income			32,959		3	32,962
Foreign currency translation adjustments, net of tax				552		552
Issuance of shares to employees and/or directors		163				163
Issuance of shares to employees and/or directors (in shares)	10,451
Conversion of Restricted Stock Units, net of shares withheld for taxes		(77)				$ (77)
Conversion of Restricted Stock Units, net of shares withheld for taxes (in shares)	13,516					13,516
Amortization of Restricted Stock Units		703				$ 703
Dividend equivalent Units accrued - Restricted Stock Units		4	(4)
Repurchase of stock		(950)				(950)
Repurchase of stock (in shares)	(57,731)
Distribution of noncontrolling entities					(1,000)	(1,000)
Dividends declared			(2,893)			(2,893)
Balance at Jun. 30, 2020	$ 5	$ 91,257	$ 554,717	$ (1,109)	$ 34	$ 644,904
Balance (in shares) at Jun. 30, 2020	48,220,811