Earnings Per Share (Details 1) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands		3 Months Ended			9 Months Ended
		Sep. 30, 2015	Jun. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Earnings Per Share [Abstract]
Net earnings from continuing operations		$ 69,616	$ 85,083	$ 62,276	$ 227,778	$ 99,411
Less: Earnings allocated to unvested restricted stock	[1]	(649)	(807)	(685)	(2,213)	(1,147)
Net earnings from continuing operations allocated to common shares		68,967	84,276	61,591	225,565	98,264
Net (loss) earnings from discontinued operations allocated to common shares		0	0	(5)	0	(1,487)
Net earnings allocated to common shares		$ 68,967	$ 84,276	$ 61,586	$ 225,565	$ 96,777
Weighted-average basic shares and unvested restricted stock outstanding (shares)		103,048	103,030	103,029	103,038	82,758
Weighted-average unvested restricted stock outstanding (shares)		(985)	(1,060)	(1,117)	(1,055)	(981)
Weighted-average basic shares outstanding (shares)		102,063	101,970	101,912	101,983	81,777
Net earnings from continuing operations (usd per share)		$ 0.68	$ 0.83	$ 0.60	$ 2.21	$ 1.20
Net loss from discontinued operations (usd per share)		0.00	0.00	0.00	0.00	(0.02)
Basic net income per share (usd per share)		0.68	0.83	0.60	2.21	1.18
Net earnings from continuing operations (usd per share)		0.68	0.83	0.60	2.21	1.20
Net loss from discontinued operations (usd per share)		0.00	0.00	0.00	0.00	(0.02)
Diluted net income per share (usd per share)		$ 0.68	$ 0.83	$ 0.60	$ 2.21	$ 1.18

[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.