Consolidated Statement Of Changes In Stockholders' Equity (USD $) In Thousands	Total	Common Stock	Additional Paid-In Capital	Retained Earnings	Treasury Shares
Balance at Dec. 31, 2009	$ 235,266	$ 274	$ 97,213	$ 141,114	$ (3,335)
Balance (in shares) at Dec. 31, 2009		27,375			(527)
Issuance of common stock under stock incentive plans, including income tax deficiencies (in shares)		90
Issuance of common stock under stock incentive plans, including income tax deficiencies	654	1	653
Issuance of common stock under Employee Stock Purchase Plan (in shares)		42
Issuance of common stock under Employee Stock Purchase Plan	294		294
Stock-based compensation expense	1,531		1,531
Nonvested stock awards (in shares)					128
Nonvested stock awards			(820)		820
Repurchase of common stock for treasury (in shares)	(423)				(455)
Repurchase of common stock for treasury	(3,067)				(3,067)
Net income	22,961			22,961
Balance at Dec. 31, 2010	257,639	275	98,871	164,075	(5,582)
Balance (in shares) at Dec. 31, 2010		27,507			(854)
Issuance of common stock under stock incentive plans, including income tax deficiencies (in shares)		64
Issuance of common stock under stock incentive plans, including income tax deficiencies	404	1	403
Issuance of common stock under Employee Stock Purchase Plan (in shares)		42
Issuance of common stock under Employee Stock Purchase Plan	380		380
Stock-based compensation expense	824		824
Nonvested stock awards (in shares)					93
Nonvested stock awards			(633)		633
Tax benefit from stock-based compensation	112		112
Repurchase of common stock for treasury (in shares)	(461)				(487)
Repurchase of common stock for treasury	(4,029)				(4,029)
Dividend payment	(10,588)			(10,588)
Net income	28,787			28,787
Balance at Dec. 31, 2011	273,529	276	99,957	182,274	(8,978)
Balance (in shares) at Dec. 31, 2011		27,613			(1,248)
Issuance of common stock under stock incentive plans, including income tax deficiencies (in shares)		110
Issuance of common stock under stock incentive plans, including income tax deficiencies	872	1	871
Issuance of common stock under Employee Stock Purchase Plan (in shares)		49
Issuance of common stock under Employee Stock Purchase Plan	515	1	514
Stock-based compensation expense	1,494		1,494
Nonvested stock awards (in shares)					177
Nonvested stock awards			(1,314)		1,314
Shares withheld for taxes paid on stock awards (in Shares)	(52)				(52)
Shares withheld for taxes paid on stock awards	(504)				(504)
Tax benefit from stock-based compensation	213		213
Repurchase of common stock for treasury (in shares)	(762)				(762)
Repurchase of common stock for treasury	(7,813)				(7,813)
Dividend payment	(10,074)			(10,074)
Net income	33,071			33,071
Balance at Dec. 31, 2012	$ 291,303	$ 278	$ 101,735	$ 205,271	$ (15,981)
Balance (in shares) at Dec. 31, 2012		27,772			(1,885)