Earnings Per Share (Summary Of Calculation Of Basic And Diluted Earnings Per Share) (Details) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Earnings Per Share [Abstract]
Income from continuing operations	$ 14,351	$ 17,736	$ 49,628	$ 59,466
Discontinued operations	0	1,072	0	3,552
Net income	$ 14,351	$ 18,808	$ 49,628	$ 63,018
Weighted average common shares outstanding, basic	27,830,311	27,729,560	27,799,750	27,711,474
Income from continuing operations per common share, basic	$ 0.52	$ 0.64	$ 1.78	$ 2.14
Discontinued operations per common share, basic	$ 0.00	$ 0.04	$ 0.00	$ 0.13
Net income per common share	$ 0.52	$ 0.68	$ 1.78	$ 2.27
Weighted average common shares outstanding, diluted	27,830,311	27,729,560	27,799,750	27,711,474
Stock options, diluted	32,271	59,010	29,129	82,130
Restricted shares, diluted	0	1,155	0	1,546
Average dilutive common shares outstanding	27,862,582	27,789,725	27,828,879	27,795,150
Income from continuing operations per common share	$ 0.52	$ 0.64	$ 1.78	$ 2.14
Discontinued operations per common share	$ 0.00	$ 0.04	$ 0.00	$ 0.13
Net income per common share	$ 0.52	$ 0.68	$ 1.78	$ 2.27
Stock options with an exercise price in excess of the market price for our common shares	917	37,048	1,972	14,962
Common Stock, Dividends, Per Share, Declared	$ 0.67	$ 0.615	$ 1.97	$ 1.85