EARNINGS PER SHARE (Details) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income (Numerator)
Net income	$ 207,694	$ 65,000	$ 29,310	$ 43,994	$ 444,800	$ 32,566	$ 46,035	$ 70,703	$ 345,998	$ 594,104	$ 250,762
Net income attributable to noncontrolling interests									(4,757)	(18,091)	(5,461)
Numerator for diluted earnings available to common shareholders									$ 341,241	$ 576,013	$ 245,301
Shares (Denominator)
Weighted average common shares outstanding (in shares)									100,913	99,844	93,567
Dilutive effect of outstanding stock settled appreciation rights and stock options									805	945	866
Weighted-average common and common equivalent shares outstanding (in shares)									101,718	100,789	94,433
Antidilutive Securities Excluded from Computation
Antidilutive dilutive securities excluded from calculation of diluted earnings per share (in shares)									1,325	450	556