Stock-Based Compensation (Summary Of Stock-Based Compensation Expense And Related Tax Benefits) (Details) (USD $)	3 Months Ended
	Mar. 31, 2012		Mar. 31, 2011
Stock-Based Compensation [Abstract]
Stock based compensation expense related to restricted share awards	$ 1,000,000		$ 900,000
Stock based compensation expense related to stock options
Total stock based compensation expense	993,000		882,000
Income tax benefit from restricted share awards	400,000		1,200,000
Income tax benefit from stock options	100,000		2,000,000
Total income tax benefit from stock based compensation	500,000		3,200,000
Excess tax benefit from vested restricted shares			900,000	[1]
Excess tax benefit from stock options exercised	100,000	[1]	2,000,000	[1]
Total excess tax benefit from stock based compensation	$ 97,000		$ 2,878,000

[1] Excess tax benefits, which represent cash flows from tax deductions in excess of compensation expense recognized for stock options exercised and vested restricted shares, are classified as financing cash flows in the Company's condensed unaudited consolidated statements of cash flows.