UNAUDITED CONDENSED CONSOLIDATED STATEMENTS OF STOCKHOLDERS’ EQUITY - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Retained Earnings	Accumulated Other Comprehensive Income	Cumulative Effect Period of Adoption Adjustment	Cumulative Effect Period of Adoption Adjustment Retained Earnings
Beginning balance (in shares) at Dec. 31, 2019		21,964,809
Beginning balance at Dec. 31, 2019	$ 1,462,710	$ 220	$ 1,309,438	$ 152,819	$ 233	$ (3,311)	$ (3,311)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation	3,025		3,025
Exercise of stock options, net (in shares)		14,315
Exercise of stock options, net	847		847
Issuance of restricted stock, net (in shares)		236,232
Issuance of restricted stock, net	(25,797)	$ 2	(25,799)
Repurchase of common stock (in shares)		(1,769)
Repurchase of common stock	(247)		(105)	(142)
Common stock dividends	(13,339)			(13,339)
Foreign currency translation adjustment	0
Unrealized gains (losses) on marketable securities, net of tax	20				20
Net income	35,239			35,239
Ending balance (in shares) at Mar. 31, 2020		22,213,587
Ending balance at Mar. 31, 2020	1,459,147	$ 222	1,287,406	171,266	253
Beginning balance (in shares) at Dec. 31, 2020		24,418,939
Beginning balance at Dec. 31, 2020	1,748,319	$ 244	1,519,549	179,646	48,880
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation	3,900		3,868	32
Exercise of stock options, net (in shares)		799
Exercise of stock options, net	70		70
Issuance of restricted stock, net (in shares)		231,467
Issuance of restricted stock, net	(2,339)	$ 3	(2,342)
Common stock dividends	(14,786)			(14,786)
Foreign currency translation adjustment	(8,712)				(8,712)
Unrealized gains (losses) on marketable securities, net of tax	(104)				(104)
Net income	9,577			9,577
Ending balance (in shares) at Mar. 31, 2021		24,651,205
Ending balance at Mar. 31, 2021	$ 1,735,925	$ 247	$ 1,521,145	$ 174,469	$ 40,064