Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Net income (loss)	$ 353,526	$ (5,785)	$ 127,669
Other comprehensive income (loss):
Change in fair value of derivative instruments designated as cash flow hedges (net of income tax effect of $(234) and $16,512)	(407)	30,405	0
Accumulated other comprehensive income	26,942	26,758
Reclassification of realized loss on interest rate swap agreements designated as cash flow hedges (net of income tax effect of $171 and $423)	440	777	0
Foreign currency translation adjustment	151	(758)	(408)
Other comprehensive income (loss), net of tax	184	30,424	(408)
Comprehensive income	353,710	24,639	127,261
Less: income attributable to non-controlling interest	8,928	7,732	16,580
Comprehensive income attributable to shareholders	344,782	16,907	110,681
Accumulated Other Comprehensive (Loss) Income
Other comprehensive income (loss):
Change in fair value of derivative instruments designated as cash flow hedges (net of income tax effect of $(234) and $16,512)	(407)	30,405
Accumulated other comprehensive income	26,942	26,758	$ (3,666)
Reclassification of realized loss on interest rate swap agreements designated as cash flow hedges (net of income tax effect of $171 and $423)	440	777
Foreign currency translation adjustment	151	(758)
Comprehensive income	$ 184	$ 30,424