Industry Segments - Corporate Expenses (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Segment Reporting Information [Line Items]
General and administrative expense	$ 36,295	$ 33,617	$ 70,572	$ 64,420
Depreciation, amortization, and accretion	31,817	28,979	62,445	55,420
Interest expense, net	18,529	18,379	36,908	33,352
Fair Value Adjustment of Warrants			(1,113)	201
Other (income) expense, net	627	3,808	(324)	6,584
Income (Loss) from Continuing Operations, Net of Tax, Including Portion Attributable to Noncontrolling Interest	8,201	12,132	26,875	33,189
Corporate Overhead [Member]
Segment Reporting Information [Line Items]
General and administrative expense	14,350	11,871	26,439	24,469
Depreciation, amortization, and accretion	172	164	340	315
Interest expense, net	5,696	4,877	11,038	8,884
Fair Value Adjustment of Warrants	(1,520)	2,195	(1,113)	201
Other (income) expense, net	605	220	286	370
Income (Loss) from Continuing Operations, Net of Tax, Including Portion Attributable to Noncontrolling Interest	$ 19,303	$ 19,327	$ 36,990	$ 34,239