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
	Mar. 31, 2015	Mar. 31, 2014
Earnings Per Share [Abstract]
Net income attributable to common stockholders	$ 29,683	$ 23,533
BASIC:
Weighted Average Number of Shares Outstanding, Basic	37,558,067	33,051,415
Net income per common share attributable to common stockholders	$ 0.79	$ 0.71
DILUTED:
Weighted average common shares outstanding, diluted	37,558,067	33,051,415
Stock options, diluted	68,257	33,817
Incremental Common Shares Attributable to Dilutive Effect of Conversion of Debt Securities	18,941	0
Average dilutive common shares outstanding	37,645,265	33,085,232
Net income per common share attributable to common stockholders	$ 0.79	$ 0.71
Incremental shares excluded since anti-dilutive:
Stock options with an exercise price in excess of the market price for our common shares	5,666	40,153
Common Stock, Dividends, Per Share, Declared	$ 0.85	$ 0.77