Earnings Per Share (Reconciliation Of Amounts Used To Calculate Basic And Diluted Earnings Per Share) (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2010	Sep. 30, 2010	Jun. 30, 2010	Mar. 31, 2010	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Earnings Per Share [Abstract]
(Loss) income from continuing operations	$ 31,309	$ 22,055	$ 9,180	$ (108,844)	$ 17,630	$ 30,661	$ 18,035	$ 26,426	$ (46,300)	$ 92,752	$ 77,600
Provision for income taxes from discontinued operations									(20,155)	21	672
Income (loss) from discontinued operations	(20,536)	127	127	127	126	127	(360)	128	20,155	(21)	(672)
Net (loss) income	$ 51,845	$ 21,928	$ 9,053	$ (108,971)	$ 17,504	$ 30,534	$ 18,395	$ 26,298	$ (26,145)	$ 92,731	$ 76,928
Weighted average number of common shares outstanding									35,950	34,307	33,679
(Loss) income from continuing operations, Basic	$ 0.87	$ 0.61	$ 0.26	$ (3.07)	$ 0.50	$ 0.89	$ 0.53	$ 0.78	$ (1.29)	$ 2.70	$ 2.30
Income (loss) from discontinued operations, Basic	$ 0.57	$ 0.00	$ (0.01)	$ 0.00	$ 0.00	$ 0.00	$ 0.01	$ 0.00	$ 0.56	$ 0.00	$ (0.02)
Net (loss) income	$ 1.44	$ 0.61	$ 0.25	$ (3.07)	$ 0.50	$ 0.89	$ 0.54	$ 0.78	$ (0.73)	$ 2.70	$ 2.28
Effect of dilutive securities, Assuming dilution										1,337	509
Weighted average number of common and common equivalent shares outstanding, Assuming dilution									35,950	35,644	34,188
(Loss) income from continuing operations, Assuming dilution	$ 0.85	$ 0.60	$ 0.25	$ (3.07)	$ 0.48	$ 0.86	$ 0.51	$ 0.75	$ (1.29)	$ 2.60	$ 2.27
Income (loss) from discontinued operations, Assuming dilution	$ 0.56	$ 0.00	$ 0.00	$ 0.00	$ 0.00	$ 0.00	$ 0.01	$ 0.00	$ 0.56	$ 0.00	$ (0.02)
Net (loss) income	$ 1.41	$ 0.60	$ 0.25	$ (3.07)	$ 0.48	$ 0.86	$ 0.52	$ 0.75	$ (0.73)	$ 2.60	$ 2.25