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, 2016	$ 5	$ 162,128	$ 335,218		$ 1,219	$ 498,570
Balance (in shares) at Dec. 31, 2016	51,576,442
Increase (Decrease) in Stockholders' Equity Roll Forward
Net income			72,354		4,496	76,850
Issuance of shares to employees and/or directors		2,210				2,210
Issuance of shares to employees and/or directors (in shares)	88,661
Amortization of Restricted Stock Units		1,126				1,126
Dividend equivalent Units accrued - Restricted Stock Units		37	(37)
Repurchase of stock		(4,999)				(4,999)
Repurchase of stock (in shares)	(216,350)
Dividends declared			(11,574)			(11,574)
Balance at Dec. 31, 2017	$ 5	160,502	395,961		5,715	562,183
Balance (in shares) at Dec. 31, 2017	51,448,753
Increase (Decrease) in Stockholders' Equity Roll Forward
Net income			77,461		10,132	87,593
Foreign currency translation adjustments, net of tax				$ (908)		(908)
Issuance of shares to employees and/or directors		2,245				2,245
Issuance of shares to employees and/or directors (in shares)	91,911
Amortization of Restricted Stock Units		1,253				1,253
Dividend equivalent Units accrued - Restricted Stock Units		48	(48)
Repurchase of stock		(20,000)				(20,000)
Repurchase of stock (in shares)	(825,146)
Distribution of noncontrolling entities					(13,084)	(13,084)
Dividends declared			(12,299)			(12,299)
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			82,327		1,770	84,097
Foreign currency translation adjustments, net of tax				984		984
Issuance of shares to employees and/or directors		2,998				2,998
Issuance of shares to employees and/or directors (in shares)	144,261
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
Amortization of Restricted Stock Units		1,579				1,579
Dividend equivalent Units accrued - Restricted Stock Units		24	(24)
Repurchase of stock		(50,000)				(50,000)
Repurchase of stock (in shares)	(2,316,960)
Distribution of noncontrolling entities					(3,505)	(3,505)
Dividends declared			(12,087)			(12,087)
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