CONSOLIDATED STATEMENT OF CHANGES IN STOCKHOLDERS' EQUITY (Unaudited) (USD $) In Thousands	Preferred Stock [Member]	Common Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	Treasury Stock [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Total
Balance at Dec. 31, 2010	$ 0	$ 34	$ 232,524	$ 206,210	$ (4,494)	$ (3,433)	$ 430,841
Comprehensive income:
Net income	0	0	0	19,377	0	0	19,377
Net change in fair value of interest rate swaps, net of income taxes of $648	0	0	0	0	0	1,000	1,000
Foreign currency translation adjustment	0	0	0	0	0	(340)	(340)
Total comprehensive income							20,037
Repurchases of common stock	0	(2)	0	0	(23,688)	0	(23,690)
Exercise of stock options	0	1	4,811	0	0	0	4,812
Tax effect of stock options and restricted stock units	0	0	(1,053)	0	0	0	(1,053)
Share-based employee compensation expense	0	0	6,803	0	0	0	6,803
Issuance of stock in conjunction with Navvis acquisition	0	0	5,437	0	0	0	5,437
Balance at Sep. 30, 2011	$ 0	$ 33	$ 248,522	$ 225,587	$ (28,182)	$ (2,773)	$ 443,187