Earnings (Loss) Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended					9 Months Ended
	Sep. 30, 2020		Jun. 30, 2020	Sep. 30, 2019		Sep. 30, 2020	Sep. 30, 2019
Earnings Per Share [Abstract]
Net earnings from continuing operations	$ 45,503			$ 110,026		$ (1,354,404)	$ 350,755
Less: Earnings allocated to unvested restricted stock	(578)	[1]		(1,369)	[1]	(1,603)	(3,725)
Net earnings allocated to common shares	$ 44,925			$ 108,657		$ (1,356,007)	$ 347,030
Weighted-average basic shares and unvested restricted stock outstanding (shares)	118,438			119,831		118,469	120,691
Weighted-average unvested restricted stock outstanding (shares)	(1,684)			(1,622)		(1,596)	(1,480)
Weighted-average basic shares outstanding (shares)	116,754			118,209		116,873	119,211
Basic net income per share (usd per share)	$ 0.38		$ 0.28	$ 0.92		$ (11.60)	$ 2.91
Net earnings from continuing operations allocated to common shares	$ 44,925			$ 108,657		$ (1,356,007)	$ 347,030
Diluted net income per share (usd per share)	$ 0.38		$ 0.28	$ 0.92		$ (11.60)	$ 2.91

[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.