Earnings and Dividends Per Share (Summary Of Calculation Of Basic And Diluted Earnings Per Share) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Earnings Per Share [Abstract]
Net income attributable to common stockholders	$ 33,600	$ 25,250	$ 94,466	$ 74,080
BASIC:
Weighted Average Number of Shares Outstanding, Basic	37,566,221	33,055,992	37,563,503	33,053,386
Net income per common share attributable to common stockholders	$ 0.89	$ 0.76	$ 2.51	$ 2.24
Income (Loss) from Continuing Operations, Per Diluted Share	$ 0.89	$ 0.76
DILUTED:
Weighted average common shares outstanding, diluted	37,566,221	33,055,992	37,563,503	33,053,386
Stock options, diluted	16,920	32,578	42,024	33,643
Incremental Common Shares Attributable to Dilutive Effect of Conversion of Debt Securities			6,314	0
Average dilutive common shares outstanding	37,583,141	33,088,570	37,611,841	33,087,029
Net income per common share attributable to common stockholders	$ 0.89	$ 0.76	$ 2.51	$ 2.24
Income (Loss) from Continuing Operations, Per Basic Share	$ 0.89	$ 0.76
Incremental shares excluded since anti-dilutive:
Stock options with an exercise price in excess of the market price for our common shares	107,993	24,659	42,052	26,734
Common Stock, Dividends, Per Share, Declared	$ 0.85	$ 0.77	$ 2.55	$ 2.31