Industry Segments - Corporate Expenses (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Segment Reporting Information [Line Items]
General and administrative expense	$ 30,803	$ 26,751
Depreciation, amortization, and accretion	26,441	26,524
Other (income) expense, net	2,776	461
Warrants fair value adjustment	(1,995)	(5,976)
Income (Loss) from Continuing Operations, Net of Tax, Including Portion Attributable to Noncontrolling Interest	21,057	4,245
Interest expense, net	14,973	13,767
Corporate Overhead [Member]
Segment Reporting Information [Line Items]
General and administrative expense	12,598	9,555
Depreciation, amortization, and accretion	151	91
Other (income) expense, net	150	428
Warrants fair value adjustment	(1,994)	(5,976)
Income (Loss) from Continuing Operations, Net of Tax, Including Portion Attributable to Noncontrolling Interest	14,912	7,872
Interest expense, net	$ 4,007	$ 3,774