Earnings (Loss) Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended					6 Months Ended
	Jun. 30, 2020		Mar. 31, 2020	Jun. 30, 2019		Jun. 30, 2020	Jun. 30, 2019
Earnings Per Share [Abstract]
Net earnings from continuing operations	$ 33,204			$ 128,125		$ (1,399,907)	$ 240,729
Less: Earnings allocated to unvested restricted stock	(362)	[1]		(1,190)	[1]	(1,251)	(2,343)
Net earnings allocated to common shares	$ 32,842			$ 126,935		$ (1,401,158)	$ 238,386
Weighted-average basic shares and unvested restricted stock outstanding (shares)	118,192			120,042		118,484	121,128
Weighted-average unvested restricted stock outstanding (shares)	(1,606)			(1,462)		(1,551)	(1,407)
Weighted-average basic shares outstanding (shares)	116,586			118,580		116,933	119,721
Basic net income per share (usd per share)	$ 0.28		$ (12.23)	$ 1.07		$ (11.98)	$ 1.99
Net earnings from continuing operations allocated to common shares	$ 32,842			$ 126,935		$ (1,401,158)	$ 238,386
Diluted net income per share (usd per share)	$ 0.28		$ (12.23)	$ 1.07		$ (11.98)	$ 1.99

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