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	53,373			53,373
Other comprehensive gain (loss)	44				44
Purchase of Company common stock (in shares)		(384,000)				384,000
Purchase of Company common stock	(27,880)					$ (27,880)
Reissuance of treasury stock (in shares)		165,000				(165,000)
Reissuance of treasury stock	3,886	$ 0	(2,506)			$ 6,392
Net issuance of shares for stock plans (in shares)		(8,000)
Net issuance of shares for stock plans	0
Repurchase of restricted shares for taxes (in shares)		(23,000)
Repurchase of restricted shares for taxes	(1,731)		(1,731)
Stock-based compensation	8,016		8,016
Dividends on common stock	0		0	0
Dividends on common stock in excess of retained earnings	(33,562)		(33,562)
Common stock, shares, outstanding, ending (in shares) at Sep. 30, 2018		17,743,000
Stockholders' equity balance, ending of the period at Sep. 30, 2018	(213,394)	$ 250	246,625	(16,567)	(61)	$ (443,641)
Treasury stock, shares, ending (in shares) at Sep. 30, 2018						7,248,000
Common stock, shares, outstanding, beginning (in shares) at Jun. 30, 2018		17,803,000
Stockholders' equity balance, beginning of the period at Jun. 30, 2018	(223,251)	$ 250	254,912	(40,154)	(61)	$ (438,198)
Treasury stock, shares, beginning (in shares) at Jun. 30, 2018						7,202,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	23,587			23,587
Purchase of Company common stock (in shares)		(108,000)				108,000
Purchase of Company common stock	(7,877)					$ (7,877)
Reissuance of treasury stock (in shares)		62,000				(62,000)
Reissuance of treasury stock	3,266	$ 0	832			$ 2,434
Net issuance of shares for stock plans (in shares)		(10,000)
Net issuance of shares for stock plans	0
Repurchase of restricted shares for taxes (in shares)		(4,000)
Repurchase of restricted shares for taxes	(331)		(331)
Stock-based compensation	2,375		2,375
Dividends on common stock	0		0	0
Dividends on common stock in excess of retained earnings	(11,163)		(11,163)
Common stock, shares, outstanding, ending (in shares) at Sep. 30, 2018		17,743,000
Stockholders' equity balance, ending of the period at Sep. 30, 2018	$ (213,394)	$ 250	246,625	(16,567)	(61)	$ (443,641)
Treasury stock, shares, ending (in shares) at Sep. 30, 2018						7,248,000
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	$ 76,950			76,950
Purchase of Company common stock (in shares)		(1,067,000)				1,067,000
Purchase of Company common stock	$ (90,073)					$ (90,073)
Reissuance of treasury stock (in shares)	260,474	260,000				(260,000)
Reissuance of treasury stock	$ 10,671	$ (1)	(736)			$ 11,408
Net issuance of shares for stock plans (in shares)		(22,000)
Net issuance of shares for stock plans	0
Repurchase of restricted shares for taxes (in shares)		(28,000)
Repurchase of restricted shares for taxes	(2,589)		(2,589)
Stock-based compensation	8,220		8,220
Dividends on common stock	$ (35,658)		(737)	(36,395)
Common stock, shares, outstanding, ending (in shares) at Sep. 30, 2019	16,786,860	16,787,000
Stockholders' equity balance, ending of the period at Sep. 30, 2019	$ (239,782)	$ 249	243,358	45,939	(60)	$ (529,268)
Treasury stock, shares, ending (in shares) at Sep. 30, 2019	8,147,503					8,148,000
Common stock, shares, outstanding, beginning (in shares) at Jun. 30, 2019		17,252,000
Stockholders' equity balance, beginning of the period at Jun. 30, 2019	$ (215,125)	$ 249	240,555	33,832	(59)	$ (489,702)
Treasury stock, shares, beginning (in shares) at Jun. 30, 2019						7,697,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	23,917			23,917
Other comprehensive gain (loss)	(1)				(1)
Purchase of Company common stock (in shares)		(524,000)				524,000
Purchase of Company common stock	(42,717)					$ (42,717)
Reissuance of treasury stock (in shares)		73,000				(73,000)
Reissuance of treasury stock	3,733	$ 0	582			$ 3,151
Net issuance of shares for stock plans (in shares)		(10,000)
Net issuance of shares for stock plans	0
Repurchase of restricted shares for taxes (in shares)		(4,000)
Repurchase of restricted shares for taxes	(347)		(347)
Stock-based compensation	2,326		2,326
Dividends on common stock	$ (11,568)		(242)	(11,810)
Common stock, shares, outstanding, ending (in shares) at Sep. 30, 2019	16,786,860	16,787,000
Stockholders' equity balance, ending of the period at Sep. 30, 2019	$ (239,782)	$ 249	$ 243,358	$ 45,939	$ (60)	$ (529,268)
Treasury stock, shares, ending (in shares) at Sep. 30, 2019	8,147,503					8,148,000