Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Earnings per share — Basic:
Earnings from continuing operations	$ 56,185	$ 53,326
Less: Distributed and undistributed earnings allocated to unvested stock	(166)	(148)
Earnings from continuing operations available to common shareholders — Basic	$ 56,019	$ 53,178
Weighted average common shares outstanding - Basic (shares)	53,076	52,596
Earnings from continuing operations per common share — Basic (in dollars per share)	$ 1.06	$ 1.01
Earnings per share — Diluted:
Earnings from continuing operations	$ 56,185	$ 53,326
Less: Distributed and undistributed earnings allocated to unvested stock	(166)	(148)
Earnings from continuing operations available to common shareholders — Diluted	$ 56,019	$ 53,178
Weighted average common shares outstanding - Basic (shares)	53,076	52,596
Effect of dilutive equity awards (shares)	287	510
Weighted average common shares outstanding — Diluted (shares)	53,363	53,106
Earnings from continuing operations per common share — Diluted (in dollars per share)	$ 1.05	$ 1.00
Anti-dilutive equity awards not included above (shares)	1,186	184