Consolidated Statements of Stockholders' Equity - USD ($) shares in Thousands, $ in Thousands	Total	Common Stock	Paid-in Capital	Retained Earnings
Balance (in shares) at Dec. 31, 2019		52,079
Balance at Dec. 31, 2019	$ 290,140	$ 208	$ 3,631	$ 286,301
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	39,657			39,657
Stock options exercised and restricted stock awards granted (in shares)		490
Stock options exercised and restricted stock awards granted	14,173	$ 2	14,171
Share-based compensation	5,694		5,694
Stock repurchased and retired (in shares)		(335)
Stock repurchased and retired	(17,046)	$ (1)	(17,045)	0
Dividends	(9,923)			(9,923)
Balance (in shares) at Jun. 30, 2020		52,234
Balance at Jun. 30, 2020	322,695	$ 209	6,451	316,035
Balance (in shares) at Mar. 31, 2020		52,044
Balance at Mar. 31, 2020	306,323	$ 208	0	306,115
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	17,804			17,804
Stock options exercised and restricted stock awards granted (in shares)		278
Stock options exercised and restricted stock awards granted	9,676	$ 1	9,675
Share-based compensation	3,343		3,343
Stock repurchased and retired (in shares)		(88)
Stock repurchased and retired	(4,528)	$ 0	(6,567)	2,039
Dividends	(9,923)			(9,923)
Balance (in shares) at Jun. 30, 2020		52,234
Balance at Jun. 30, 2020	322,695	$ 209	6,451	316,035
Balance (in shares) at Dec. 31, 2020		52,225
Balance at Dec. 31, 2020	350,865	$ 209	5,161	345,495
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	36,991			36,991
Stock options exercised and restricted stock awards granted (in shares)		361
Stock options exercised and restricted stock awards granted	11,848	$ 2	11,846
Share-based compensation	5,793		5,793
Stock repurchased and retired (in shares)		(170)
Stock repurchased and retired	(11,803)	$ (1)	(11,802)	0
Dividends	(9,968)			(9,968)
Balance (in shares) at Jun. 30, 2021		52,416
Balance at Jun. 30, 2021	383,726	$ 210	10,998	372,518
Balance (in shares) at Mar. 31, 2021		52,424
Balance at Mar. 31, 2021	373,038	$ 210	10,957	361,871
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	20,615			20,615
Stock options exercised and restricted stock awards granted (in shares)		75
Stock options exercised and restricted stock awards granted	2,410	$ 0	2,410
Share-based compensation	3,032		3,032
Stock repurchased and retired (in shares)		(83)
Stock repurchased and retired	(5,401)	$ 0	(5,401)	0
Dividends	(9,968)			(9,968)
Balance (in shares) at Jun. 30, 2021		52,416
Balance at Jun. 30, 2021	$ 383,726	$ 210	$ 10,998	$ 372,518