CONDENSED CONSOLIDATED STATEMENTS OF CHANGES IN STOCKHOLDERS' EQUITY - USD ($) shares in Thousands, $ in Thousands	Total	Common Stock	Additional Paid-In Capital	Accumulated Other Comprehensive Income (Loss)	Retained Earnings	Treasury Stock
Balance at Dec. 31, 2018	$ 109,106	$ 12	$ 8,802	$ (173)	$ 131,344	$ (30,879)
Balance (in shares) at Dec. 31, 2018		12,117
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	77,916				77,916
Share-based compensation	4,520		4,520
Share-based compensation (in shares)		273
Options exercised by executives and directors	278		278
Options exercised by executives and directors (in shares)		10
Net shares repurchased for employee taxes	$ (14,092)		(13,600)		(492)
Net shares repurchased for employee taxes, (in shares)	(128)	(128)
Treasury stock from stock repurchases	$ (33,114)					(33,114)
Other comprehensive income	198			198
Cash dividends declared to stockholders	(39,980)				(39,980)
Balance at Dec. 31, 2019	104,832	$ 12	0	25	168,788	(63,993)
Balance (in shares) at Dec. 31, 2019		12,272
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	102,859				102,859
Share-based compensation	6,796		6,796
Share-based compensation (in shares)		17
Options exercised by executives and directors	1,597		1,597
Options exercised by executives and directors (in shares)		28
Net shares repurchased for employee taxes	$ (551)		(551)		0
Net shares repurchased for employee taxes, (in shares)	(6)	(6)
Treasury stock from stock repurchases	$ (5,000)					(5,000)
Treasury stock retired from stock repurchases	$ 0				(63,993)	63,993
Treasury stock retired from stock repurchases (in shares)	(489)
Other comprehensive income	$ 16			16
Cash dividends declared to stockholders	(53,303)				(53,303)
Balance at Dec. 31, 2020	157,246	$ 12	7,842	41	154,351	(5,000)
Balance (in shares) at Dec. 31, 2020		11,822
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	164,031				164,031
Share-based compensation	9,596		9,454		142
Share-based compensation (in shares)		55
Options exercised by executives and directors	811		811
Options exercised by executives and directors (in shares)		29
Net shares repurchased for employee taxes	$ (6,089)		(6,089)
Net shares repurchased for employee taxes, (in shares)	(22)	(28)
Treasury stock from stock repurchases	$ (55,999)					(55,999)
Treasury stock retired from stock repurchases	$ 0				(60,999)	60,999
Treasury stock retired from stock repurchases (in shares)	(284)
Other comprehensive income	$ 70			70
Cash dividends declared to stockholders	(67,192)				(67,192)
Balance at Dec. 31, 2021	$ 202,474	$ 12	$ 12,018	$ 111	$ 190,333	$ 0
Balance (in shares) at Dec. 31, 2021		11,594