Earnings Per Share (Computation Of Basic And Diluted Earnings Per Share) (Details) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Numerator (both basic and diluted):
Net income (loss)	$ (12,797)	$ 14,737	$ (21,574)	$ 34,368
Denominator:
Denominator for basic earnings per share	40,336,229	41,153,722	40,411,887	40,958,196
Stock options		167,272		195,703
Unvested restricted stock		105,092		565,695
Denominator for diluted earnings per share	40,336,229	41,426,086	40,411,887	41,719,594
Basic earnings per common share:	$ (0.32)	$ 0.36	$ (0.53)	$ 0.84
Diluted earnings per common share:	$ (0.32)	$ 0.36	$ (0.53)	$ 0.82