Business Segment Information - Reconciliation of Segment Profits to Consolidated Operating Loss (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Segment Reporting Information [Line Items]
Depreciation and amortization			$ (40,593)	$ (85,668)
Gain (loss) on disposal of assets			2,868	(2,634)
Asset impairment			(101,458)
Continuing Operations
Segment Reporting Information [Line Items]
Segment profits	$ 10,625	$ 35,584	48,934	116,566
General and administrative expenses	(25,451)	(28,529)	(90,958)	(90,471)
Depreciation and amortization	(12,976)	(17,819)	(40,593)	(51,297)
Gain (loss) on disposal of assets	5,190	(738)	5,700	(2,014)
Asset impairment	(1,830)	0	(101,458)	0
Operating loss	$ (24,442)	$ (11,502)	$ (178,375)	$ (27,216)