Stockholders' Equity (Summary Of Nonvested Stock Option Transactions Relating To Non-Qualified Stock Option Plans) (Details) (USD $)	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
No. of options, Outstanding at December 31, 2010	3,495,000
Number of options, Cancelled	(149,000)
No. of options, Outstanding at December 31, 2011	3,653,000	3,495,000
Weighted average grant date fair value, Granted	$ 9.66	$ 7.76	$ 4.17
Nonvested Stock Option [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
No. of options, Outstanding at December 31, 2010	1,289
Number of options, Granted	575
Number of options, Cancelled	(106)
Number of options, Vested	(569)
No. of options, Outstanding at December 31, 2011	1,189
Weighted average grant date fair value, Outstanding at December 31, 2010	$ 6.46
Weighted average grant date fair value, Granted	$ 9.66
Weighted average grant date fair value, Cancelled	$ 6.86
Weighted average grant date fair value, Vested	$ 6.62
Weighted average grant date fair value, Outstanding at December 31, 2011	$ 7.89