Earnings and Dividends 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								12 Months Ended
	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Earnings Per Share [Abstract]
Income from continuing operations attributable to common stockholders	$ 24,114	$ 22,035	$ 18,300	$ 14,050	$ 27,171	$ 13,282	$ 15,859	$ 16,355	$ 78,499	$ 72,667	$ 69,817
Income from discontinued operations									27,684	18,064	11,315
Net income attributable to common stockholders	$ 27,775	$ 42,744	$ 19,921	$ 15,743	$ 41,105	$ 14,350	$ 16,927	$ 18,349	$ 106,183	$ 90,731	$ 81,132
Weighted Average Number of Shares Outstanding, Basic	29,831,176	27,876,176	27,876,176	27,876,176	27,848,002	27,830,311	27,792,834	27,776,104	28,362,398	27,811,813	27,719,096
Income from continuing operations per common share, basic	$ 0.81	$ 0.79	$ 0.65	$ 0.50	$ 0.98	$ 0.48	$ 0.57	$ 0.59	$ 2.77	$ 2.61	$ 2.52
Discontinued operations per common share, basic	$ 0.12	$ 0.74	$ 0.06	$ 0.06	$ 0.50	$ 0.04	$ 0.04	$ 0.07	$ 0.97	$ 0.65	$ 0.41
Net income per common share attributable to common stockholders	$ 0.93	$ 1.53	$ 0.71	$ 0.56	$ 1.48	$ 0.52	$ 0.61	$ 0.66	$ 3.74	$ 3.26	$ 2.93
Weighted average common shares outstanding, diluted									28,362,398	27,811,813	27,719,096
Stock options, diluted									35,304	26,907	73,496
Average dilutive common shares outstanding	29,860,614	27,905,545	27,913,727	27,911,584	27,868,245	27,862,582	27,820,831	27,803,222	28,397,702	27,838,720	27,792,592
Income from continuing operations per common share	$ 0.81	$ 0.79	$ 0.65	$ 0.50	$ 0.97	$ 0.48	$ 0.57	$ 0.59	$ 2.77	$ 2.61	$ 2.51
Discontinued operations per common share	$ 0.12	$ 0.74	$ 0.06	$ 0.06	$ 0.50	$ 0.04	$ 0.04	$ 0.07	$ 0.97	$ 0.65	$ 0.41
Net income per common share attributable to common stockholders	$ 0.93	$ 1.53	$ 0.71	$ 0.56	$ 1.47	$ 0.52	$ 0.61	$ 0.66	$ 3.74	$ 3.26	$ 2.92
Stock options with an exercise price in excess of the market price for our common shares									23,883	0	16,758
Common Stock, Dividends, Per Share, Declared, Regular									$ 2.90	$ 2.64	$ 2.495
Special dividends declared per common share1									$ 0	$ 0.22	$ 0.22