Condensed Consolidated Statements of Changes In Stockholders' Equity - USD ($) $ in Thousands	Total	Capital Stock Preferred	Issued Common	Additional Paid-In Capital	Retained Earnings	Accumulated Other Comprehensive Loss	Treasury Stock
Beginning Balance at Dec. 31, 2018	$ 201,441	$ 4	$ 6,715	$ 15,375	$ 198,914	$ (164)	$ (19,403)
Comprehensive income:
Net income	9,720				9,720
Other comprehensive loss	14					14
Dividends and dividend equivalents net of estimated forfeitures	(1,714)				(1,714)
Share-based compensation	1,031			1,031
Stock shares awarded, forfeited or vested	94			(3,770)			3,864
Purchase of treasury stock for tax withholding on share-based compensation	(5,467)						(5,467)
Ending Balance at Mar. 31, 2019	205,119	4	6,715	12,636	206,851	(81)	(21,006)
Beginning Balance at Dec. 31, 2019	231,044	4	6,715	14,029	230,784	(246)	(20,242)
Comprehensive income:
Net income	9,842				9,842
Other comprehensive loss	(6)					(6)
Dividends and dividend equivalents net of estimated forfeitures	(2,059)				(2,059)
Share-based compensation	902			902
Stock shares awarded, forfeited or vested	237			(567)			804
Purchase of treasury stock for tax withholding on share-based compensation	(4,395)						(4,395)
Ending Balance at Mar. 31, 2020	$ 235,565	$ 4	$ 6,715	$ 14,364	$ 238,567	$ (252)	$ (23,833)