Earnings Per Share (Details 1) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands		3 Months Ended			6 Months Ended
		Jun. 30, 2016	Mar. 31, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Earnings Per Share [Abstract]
Net earnings from continuing operations		$ 82,168	$ 90,456	$ 85,083	$ 172,624	$ 158,162
Less: Earnings allocated to unvested restricted stock	[1]	(863)	(1,067)	(807)	(1,933)	(1,570)
Net earnings allocated to common shares		$ 81,305	$ 89,389	$ 84,276	$ 170,691	$ 156,592
Weighted-average basic shares and unvested restricted stock outstanding (shares)		121,799	121,598	103,030	121,698	103,033
Weighted-average unvested restricted stock outstanding (shares)		(1,481)	(1,392)	(1,060)	(1,436)	(1,091)
Weighted-average basic shares outstanding (shares)		120,318	120,206	101,970	120,262	101,942
Basic net income per share (usd per share)		$ 0.68	$ 0.74	$ 0.83	$ 1.42	$ 1.54
Net earnings from continuing operations allocated to common shares		$ 81,305	$ 89,389	$ 84,276	$ 170,691	$ 156,592
Diluted net income per share (usd per share)		$ 0.68	$ 0.74	$ 0.83	$ 1.42	$ 1.54

[1] Represents cash dividends paid to holders of unvested restricted stock, net of estimated forfeitures, plus undistributed earnings amounts available to holders of unvested restricted stock, if any.