Earnings Per Share (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended
Mar. 31, 2015	Mar. 31, 2014
Earnings per share — Basic:
Earnings from continuing operations	$ 53,453	$ 49,098
Less: Distributed and undistributed earnings allocated to nonvested stock	(147)	(255)
Earnings from continuing operations available to common shareholders — Basic	53,306	48,843
Weighted average common shares outstanding - Basic (shares)	52,596	52,660
Earnings from continuing operations per common share - Basic (in dollars per share)	$ 1.01	$ 0.93
Earnings per share — Diluted:
Earnings from continuing operations	53,453	49,098
Less: Distributed and undistributed earnings allocated to nonvested stock	(145)	(255)
Earnings from continuing operations available to common shareholders — Diluted	$ 53,308	$ 48,843
Weighted average common shares outstanding - Basic (shares)	52,596	52,660
Effect of dilutive equity awards (shares)	510	463
Weighted average common shares outstanding - Diluted (shares)	53,106	53,123
Earnings from continuing operations per common share - Diluted (in dollars per share)	$ 1.00	$ 0.92
Anti-dilutive equity awards not included above (shares)	184	215

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Amount of income (loss) from continuing operations attributable to the parent. Also defined as revenue less expenses and taxes from ongoing operations before extraordinary items but after deduction of those portions of income or loss from continuing operations that are allocable to noncontrolling interests.

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The amount of net income (loss) from continuing operations per each share of common stock or unit outstanding during the reporting period.

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Net income after adjustments for dividends on preferred stock (declared in the period) and/or cumulative preferred stock (accumulated for the period).

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