Business Segment Information - Reconciliation of Segment Profits to Consolidated Operating Loss (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Segment Reporting Information [Line Items]
Depreciation and amortization			$ (27,619)	$ (56,489)
Gain (loss) on disposal of assets			(2,297)	(1,797)
Asset impairment			(99,628)
Continuing Operations
Segment Reporting Information [Line Items]
Segment profits	$ 15,024	$ 38,915	38,309	80,982
General and administrative expenses	(30,445)	(30,186)	(65,515)	(61,941)
Depreciation and amortization	(12,853)	(17,296)	(27,619)	(33,478)
Gain (loss) on disposal of assets	474	(580)	511	(1,277)
Asset impairment	0	0	(99,628)	0
Operating loss	$ (27,800)	$ (9,147)	$ (153,942)	$ (15,714)