CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) shares in Thousands, $ in Thousands	Common Stock	Additional Paid-In Capital	Retained Earnings	Treasury Shares	Total
Balance at Dec. 31, 2020	$ 289	$ 119,891	$ 562,084	$ (45,937)	$ 636,327
Balance (in shares) at Dec. 31, 2020	28,943			(2,773)
Stock-based compensation expense		2,092			2,092
Restricted stock units vested (in shares)	17
Shares withheld for taxes paid on stock awards		(324)			(324)
Net income			27,476		27,476
Balance at Jun. 30, 2021	$ 289	121,659	589,560	$ (45,937)	665,571
Balance (in shares) at Jun. 30, 2021	28,960			(2,773)
Balance at Mar. 31, 2021	$ 289	120,875	572,268	$ (45,937)	647,495
Balance (in shares) at Mar. 31, 2021	28,948			(2,773)
Stock-based compensation expense		1,026			1,026
Restricted stock units vested (in shares)	12
Shares withheld for taxes paid on stock awards		(242)			(242)
Net income			17,292		17,292
Balance at Jun. 30, 2021	$ 289	121,659	589,560	$ (45,937)	665,571
Balance (in shares) at Jun. 30, 2021	28,960			(2,773)
Balance at Dec. 31, 2021	$ 290	122,354	605,766	$ (45,937)	682,473
Balance (in shares) at Dec. 31, 2021	29,025			(2,773)
Stock-based compensation expense		2,790			2,790
Restricted stock units vested (in shares)	20
Shares withheld for taxes paid on stock awards		(454)			(454)
Net income			47,190		47,190
Balance at Jun. 30, 2022	$ 290	124,690	652,956	$ (45,937)	731,999
Balance (in shares) at Jun. 30, 2022	29,045			(2,773)
Balance at Mar. 31, 2022	$ 290	123,571	627,558	$ (45,937)	705,482
Balance (in shares) at Mar. 31, 2022	29,034			(2,773)
Stock-based compensation expense		1,408			1,408
Restricted stock units vested (in shares)	11
Shares withheld for taxes paid on stock awards		(289)			(289)
Net income			25,398		25,398
Balance at Jun. 30, 2022	$ 290	$ 124,690	$ 652,956	$ (45,937)	$ 731,999
Balance (in shares) at Jun. 30, 2022	29,045			(2,773)