Earnings Per Share (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended						6 Months Ended	9 Months Ended
	Sep. 30, 2014		Jun. 30, 2014		Sep. 30, 2013		Jun. 30, 2014	Sep. 30, 2014		Sep. 30, 2013
Earnings Per Share [Abstract]
Net earnings from continuing operations	$ 62,276		$ 11,230		$ 24,140			$ 99,411		$ 42,030
Less: earnings allocated to unvested restricted stock(1)	(685)	[1]	(290)	[1]	(786)	[1]		(1,147)	[1]	(1,137)	[1]
Net earnings from continuing operations allocated to common shares	61,591		10,940		23,354			98,264		40,893
Net (loss) earnings from discontinued operations allocated to common shares	0		(675)		23			(1,487)		(24)
Net earnings allocated to common shares	$ 61,591		$ 10,265		$ 23,377			$ 96,777		$ 40,869
Weighted-average basic shares and unvested restricted stock outstanding	103,029		98,817		46,091			82,758		41,306
Less: weighted-average unvested restricted stock outstanding	(1,117)		(678)		(1,795)			(981)		(1,663)
Weighted-average basic shares outstanding	101,912		98,139		44,296			81,777		39,643
Net earnings from continuing operations	$ 0.60		$ 0.11		$ 0.53		$ 0.11	$ 1.20		$ 1.03
Net loss from discontinued operations	$ 0.00		$ (0.01)		$ 0.00			$ (0.02)		$ 0.00
Basic net income per share	$ 0.60		$ 0.10		$ 0.53		$ 0.10	$ 1.18		$ 1.03
Net earnings allocated to common shares	61,591		10,265		23,377			96,777		40,869
Net earnings from continuing operations	$ 0.60		$ 0.11		$ 0.53		$ 0.11	$ 1.20		$ 1.03
Net loss from discontinued operations	$ 0.00		$ (0.01)		$ 0.00			$ (0.02)		$ 0.00
Diluted net income per share	$ 0.60		$ 0.10		$ 0.53		$ 0.10	$ 1.18		$ 1.03

[1] (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.