Consolidated Statements of Stockholders' Deficit - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Retained Earnings	Accumulated Other Comprehensive Loss	Treasury Stock
Common stock, shares, outstanding, beginning (in shares) at Dec. 31, 2017		17,993,000
Stockholders' equity balance, beginning of the period at Dec. 31, 2017	$ (215,540)	$ 250	$ 276,408	$ (69,940)	$ (105)	$ (422,153)
Treasury stock, shares, beginning (in shares) at Dec. 31, 2017						7,029,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	29,786			29,786
Other comprehensive gain (loss)	44				44
Purchase of Company common stock (in shares)		(276,000)				276,000
Purchase of Company common stock	(20,003)					$ (20,003)
Reissuance of treasury stock (in shares)		103,000				(103,000)
Reissuance of treasury stock	620	$ 0	(3,338)			$ 3,958
Net issuance of shares for stock plans (in shares)		3,000
Net issuance of shares for stock plans	0
Repurchase of restricted shares for taxes (in shares)		(20,000)
Repurchase of restricted shares for taxes	(1,400)		(1,400)
Stock-based compensation	5,641		5,641
Dividends on common stock	0		0	0
Dividends on common stock in excess of retained earnings	(22,399)		(22,399)
Common stock, shares, outstanding, ending (in shares) at Jun. 30, 2018		17,803,000
Stockholders' equity balance, ending of the period at Jun. 30, 2018	(223,251)	$ 250	254,912	(40,154)	(61)	$ (438,198)
Treasury stock, shares, ending (in shares) at Jun. 30, 2018						7,202,000
Common stock, shares, outstanding, beginning (in shares) at Mar. 31, 2018		17,922,000
Stockholders' equity balance, beginning of the period at Mar. 31, 2018	(216,886)	$ 250	264,994	(52,867)	(58)	$ (429,205)
Treasury stock, shares, beginning (in shares) at Mar. 31, 2018						7,091,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	12,713			12,713
Other comprehensive gain (loss)	(3)				(3)
Purchase of Company common stock (in shares)		(137,000)				137,000
Purchase of Company common stock	(10,000)					$ (10,000)
Reissuance of treasury stock (in shares)		26,000				(26,000)
Reissuance of treasury stock	164	$ 0	(843)			$ 1,007
Net issuance of shares for stock plans (in shares)		(3,000)
Net issuance of shares for stock plans	0
Repurchase of restricted shares for taxes (in shares)		(5,000)
Repurchase of restricted shares for taxes	(317)		(317)
Stock-based compensation	2,273		2,273
Dividends on common stock	(295)		(295)	0
Dividends on common stock in excess of retained earnings	(10,900)		(10,900)
Common stock, shares, outstanding, ending (in shares) at Jun. 30, 2018		17,803,000
Stockholders' equity balance, ending of the period at Jun. 30, 2018	$ (223,251)	$ 250	254,912	(40,154)	(61)	$ (438,198)
Treasury stock, shares, ending (in shares) at Jun. 30, 2018						7,202,000
Common stock, shares, outstanding, beginning (in shares) at Dec. 31, 2018	17,644,267	17,644,000
Stockholders' equity balance, beginning of the period at Dec. 31, 2018	$ (202,273)	$ 250	237,726	10,414	(60)	$ (450,603)
Treasury stock, shares, beginning (in shares) at Dec. 31, 2018	7,340,631					7,341,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	$ 53,033			53,033
Other comprehensive gain (loss)	1				1
Purchase of Company common stock (in shares)		(543,000)				543,000
Purchase of Company common stock	$ (47,356)					$ (47,356)
Reissuance of treasury stock (in shares)	187,367	187,000				(187,000)
Reissuance of treasury stock	$ 6,938	$ (1)	(1,318)			$ 8,257
Net issuance of shares for stock plans (in shares)		(12,000)
Net issuance of shares for stock plans	0
Repurchase of restricted shares for taxes (in shares)		(24,000)
Repurchase of restricted shares for taxes	(2,242)		(2,242)
Stock-based compensation	5,894		5,894
Dividends on common stock	$ (24,090)		495	(24,585)
Common stock, shares, outstanding, ending (in shares) at Jun. 30, 2019	17,252,391	17,252,000
Stockholders' equity balance, ending of the period at Jun. 30, 2019	$ (215,125)	$ 249	240,555	33,832	(59)	$ (489,702)
Treasury stock, shares, ending (in shares) at Jun. 30, 2019	7,696,712					7,697,000
Common stock, shares, outstanding, beginning (in shares) at Mar. 31, 2019		17,651,000
Stockholders' equity balance, beginning of the period at Mar. 31, 2019	$ (190,821)	$ 250	239,585	24,588	(61)	$ (455,183)
Treasury stock, shares, beginning (in shares) at Mar. 31, 2019						7,324,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	21,390			21,390
Other comprehensive gain (loss)	2				2
Purchase of Company common stock (in shares)		(392,000)				392,000
Purchase of Company common stock	(35,341)					$ (35,341)
Reissuance of treasury stock (in shares)		19,000				(19,000)
Reissuance of treasury stock	170	$ (1)	(651)			$ 822
Net issuance of shares for stock plans (in shares)		(21,000)
Net issuance of shares for stock plans	0
Repurchase of restricted shares for taxes (in shares)		(5,000)
Repurchase of restricted shares for taxes	(425)		(425)
Stock-based compensation	1,787		1,787
Dividends on common stock	$ (11,887)		259	(12,146)
Common stock, shares, outstanding, ending (in shares) at Jun. 30, 2019	17,252,391	17,252,000
Stockholders' equity balance, ending of the period at Jun. 30, 2019	$ (215,125)	$ 249	$ 240,555	$ 33,832	$ (59)	$ (489,702)
Treasury stock, shares, ending (in shares) at Jun. 30, 2019	7,696,712					7,697,000