Industry Segments - Corporate Expenses (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Segment Reporting Information [Line Items]
General and administrative expense	$ 34,277	$ 30,803
Depreciation, amortization, and accretion	30,628	26,441
Other (income) expense, net	(951)	2,776
Fair Value Adjustment of Warrants	407	(1,994)
Income (Loss) from Continuing Operations, Net of Tax, Including Portion Attributable to Noncontrolling Interest	18,674	21,057
Interest expense, net	18,379	14,973
Corporate Overhead [Member]
Segment Reporting Information [Line Items]
General and administrative expense	12,089	12,598
Depreciation, amortization, and accretion	168	151
Other (income) expense, net	(319)	150
Fair Value Adjustment of Warrants	407	(1,994)
Income (Loss) from Continuing Operations, Net of Tax, Including Portion Attributable to Noncontrolling Interest	17,687	14,912
Interest expense, net	$ 5,342	$ 4,007