Income Taxes - Provision (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017		Dec. 31, 2016
Current tax provision (benefit):
Federal	$ (21,598)	$ 5,853		$ (3,801)
State	1,465	180		111
Foreign	1,575
Total current tax provision (benefit)	(18,558)	6,033		(3,690)
Deferred tax provision (benefit):
Federal	92,250	(166,890)		(77,430)
State	12,250	20,133		(6,106)
Total deferred tax provision (benefit)	104,500	(146,757)		(83,536)
Provision (benefit) for income taxes	$ 85,942	$ (140,724)	[1]	$ (87,226)	[1]

[1] Amounts adjusted due to the adoption of Accounting Standards Update No. 2014-09, Revenue from Contracts with Customers (Topic 606). See Note 1 to the financial statements of this report for additional information.