Business Segment Information - Reconciliation of Segment Profits to Consolidated Operating Loss (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Segment Reporting [Abstract]
Segment profits	$ 39,899	$ 55,935	$ 131,942	$ 166,695
General and administrative expenses	(32,125)	(39,599)	(102,450)	(132,038)
Depreciation and amortization	(29,179)	(32,754)	(85,668)	(94,150)
Loss on disposal of assets	(837)	(191)	(2,634)	(3,891)
Asset impairment	(3,216)	0	(3,216)	0
Operating loss	$ (25,458)	$ (16,609)	$ (62,026)	$ (63,384)

Amount of write-down of assets recognized in the income statement. Includes, but is not limited to, losses from tangible assets, intangible assets and goodwill.

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The aggregate expense recognized in the current period that allocates the cost of tangible assets, intangible assets, or depleting assets to periods that benefit from use of the assets.

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Amount of gain (loss) on sale or disposal of property, plant and equipment assets, excluding oil and gas property and timber property.

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The aggregate total of expenses of managing and administering the affairs of an entity, including affiliates of the reporting entity, which are not directly or indirectly associated with the manufacture, sale or creation of a product or product line.

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Aggregate revenue less cost of goods and services sold or operating expenses directly attributable to the revenue generation activity.

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The net result for the period of deducting operating expenses from operating revenues.

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