Earnings Per Share Computation Of Basic And Diluted Earnings Per Common Share (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
Numerator:
Net income from continuing operations	$ 21,594	$ 21,469
Net income from discontinued operations	0	1,641
Net income	21,594	23,110
Denominator:
Basic earnings per share - Continuing operations (in dollars per share)	$ 0.38	$ 0.37
Basic earnings per share - Discontinued operations (in dollars per share)	$ 0.00	$ 0.03
Basic earnings per share (in dollars per share)	$ 0.38	$ 0.40
Numerator:
Net income from continuing operations	21,594	21,469
Net income from discontinued operations	0	1,641
Net income	21,594	23,110
Denominator:
Diluted earnings per share - Continuing operations (in dollars per share)	$ 0.37	$ 0.36
Diluted earnings per share - Discontinued operations (in dollars per share)	$ 0.00	$ 0.03
Diluted earnings per share (in dollars per share)	$ 0.37	$ 0.39
Basic earnings per share [Member]
Numerator:
Net income from continuing operations	21,594	21,469
Net income from discontinued operations	0	1,641
Net income	21,594	23,110
Income allocated to participating securities	(164)	(202)
Net income available to common shareholders	21,430	22,908
Denominator:
Weighted average common shares outstanding – basic	57,003	57,807
Numerator:
Net income from continuing operations	21,594	21,469
Net income from discontinued operations	0	1,641
Net income	21,594	23,110
Denominator:
Weighted average common shares outstanding – basic	57,003	57,807
Diluted earnings per share [Member]
Numerator:
Net income from continuing operations	21,594	21,469
Net income from discontinued operations	0	1,641
Net income	21,594	23,110
Denominator:
Weighted average common shares outstanding – basic	57,003	57,807
Numerator:
Net income from continuing operations	21,594	21,469
Net income from discontinued operations	0	1,641
Net income	21,594	23,110
Income allocated to participating securities	(164)	(201)
Net income available to common shareholders	$ 21,430	$ 22,909
Denominator:
Weighted average common shares outstanding – basic	57,003	57,807
Diluted effect of stock options and PVRSUs	583	493
Weighted average common shares outstanding – diluted	57,586	58,300