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 Income (Loss)	Treasury Stock
Beginning Balance at Dec. 31, 2014	$ 104,365	$ 4	$ 6,715	$ 10,931	$ 88,427	$ (732)	$ (980)
Comprehensive income (loss):
Net Income (Loss)	26,191				26,191
Other comprehensive income (loss)	232					232
Dividends and dividend equivalents, net of estimated forfeitures	(1,087)				(1,087)
Share-based compensation	999			999
Excess tax benefits	453			453
Stock shares awarded, forfeited or vested	415						415
Stock shares repurchased	(15,408)						(15,408)
Ending Balance at Dec. 31, 2015	116,160	4	6,715	12,383	113,531	(500)	(15,973)
Comprehensive income (loss):
Net Income (Loss)	31,184				31,184
Other comprehensive income (loss)	127					127
Dividends and dividend equivalents, net of estimated forfeitures	(2,063)				(2,063)
Share-based compensation	1,896			1,896
Stock shares awarded, forfeited or vested	506						506
Stock shares repurchased	(1,518)						(1,518)
Ending Balance at Dec. 31, 2016	146,292	4	6,715	14,279	142,652	(373)	(16,985)
Comprehensive income (loss):
Net Income (Loss)	41,823				41,823
Other comprehensive income (loss)	62					62
Dividends and dividend equivalents, net of estimated forfeitures	(17,346)				(17,346)
Share-based compensation	2,065			2,065
Stock shares awarded, forfeited or vested	497			(2,432)			2,929
Stock shares repurchased	(4,663)						(4,663)
Ending Balance at Dec. 31, 2017	$ 168,730	$ 4	$ 6,715	$ 13,912	$ 167,129	$ (311)	$ (18,719)