Share-Based Compensation (Summary Of Stock Option Plans) (Details) (USD $)	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Incentive Stock Option Plans [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted Average price, Beginning of period	$ 10.24	$ 8.48	$ 7.55
Granted, Weighted Average price	$ 16.11	$ 14.31	$ 10.39
Cancelled, Weighted Average price	$ 12.49	$ 9.29	$ 12.35
Exercised, Weighted Average price	$ 6.72	$ 7.27	$ 5.70
Weighted Average price, End of period	$ 11.73	$ 10.24	$ 8.48
Number of Shares, Beginning of period	1,974,000	1,904,000	1,532,000
Granted, Number of Shares	432,000	514,000	591,000
Cancelled, Number of Shares	(84,000)	(33,000)	(46,000)
Exercised, Number of Shares	(227,000)	(411,000)	(173,000)
Number of Shares, End of period	2,095,000	1,974,000	1,904,000
Non-Qualified Option Plans [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted Average price, Beginning of period	$ 7.04	$ 6.05	$ 5.85
Granted, Weighted Average price	$ 16.11	$ 14.31	$ 10.39
Cancelled, Weighted Average price	$ 13.93	$ 9.20	$ 10.76
Exercised, Weighted Average price	$ 3.47	$ 6.87	$ 5.49
Weighted Average price, End of period	$ 9.02	$ 7.04	$ 6.05
Number of Shares, Beginning of period	1,028,000	1,173,000	1,317,000
Granted, Number of Shares	78,000	156,000	41,000
Cancelled, Number of Shares	(12,000)	(8,000)	(3,000)
Exercised, Number of Shares	(277,000)	(293,000)	(182,000)
Number of Shares, End of period	817,000	1,028,000	1,173,000