Nature Of Operations And Significant Accounting Policies (Computation Of Basic And Diluted Earnings Per Share) (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended												12 Months Ended
	Dec. 31, 2012	Sep. 30, 2012		Jun. 30, 2012		Mar. 31, 2012		Dec. 31, 2011	Sep. 30, 2011		Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Accounting Policies [Abstract]
Income from continuing operations													$ 196,189	$ 22,816	$ 152,980
Less: Noncontrolling interest in subsidiaries’ earnings													828	201	20
Income from continuing operations attributable to common shareholders													195,361	22,615	152,960
Discontinued operations, net of tax	0	901		19,909		822	[1]	878	1,187		710	925	21,632	3,700	1,210
Net income attributable to common shareholders	$ 45,644	$ 57,125	[2]	$ 62,562	[3]	$ 51,662	[4]	$ (125,129)	$ 52,540	[5]	$ 50,437	$ 48,467	$ 216,993	$ 26,315	$ 154,170
Average basic shares outstanding													57,443	58,120	58,601
Effect of dilutive stock options													850	1,084	961
Average diluted shares outstanding													58,293	59,204	59,562
Earnings per share - basic:
Income from continuing operations attributable to common shareholders	$ 0.80	$ 0.99		$ 0.74		$ 0.88		$ (2.18)	$ 0.88		$ 0.85	$ 0.82	$ 3.40	$ 0.39	$ 2.61
Discontinued operations, net of tax	$ 0.00	$ 0.02		$ 0.34		$ 0.01		$ 0.02	$ 0.02		$ 0.01	$ 0.02	$ 0.38	$ 0.06	$ 0.02
Net income attributable to common shareholders	$ 0.80	$ 1.00		$ 1.08		$ 0.89		$ (2.16)	$ 0.91		$ 0.87	$ 0.83	$ 3.78	$ 0.45	$ 2.63
Earnings per share - diluted:
Income from continuing operations attributable to common shareholders	$ 0.79	$ 0.97		$ 0.73		$ 0.86		$ (2.18)	$ 0.87		$ 0.84	$ 0.80	$ 3.35	$ 0.38	$ 2.57
Discontinued operations, net of tax	$ 0.00	$ 0.02		$ 0.34		$ 0.01		$ 0.02	$ 0.02		$ 0.01	$ 0.02	$ 0.37	$ 0.06	$ 0.02
Net income attributable to common shareholders	$ 0.79	$ 0.99		$ 1.07		$ 0.88		$ (2.16)	$ 0.89		$ 0.85	$ 0.81	$ 3.72	$ 0.44	$ 2.59

[1] Includes $18,276 gain on divestiture, net of tax.

[2] Includes the impact of item (j) cited above, net of tax.

[3] Includes the impact of item (f) cited above, net of tax.

[4] Includes the impact of items (a) and (c) cited above, net of tax.

[5] Includes the impact of item (l) cited above, net of tax.