Income Taxes - Current and Deferred (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Current:
U.S. federal	$ (32,351)	$ (160,761)	$ (19,937)
State	1,811	(810)	2,871
Current Income Tax Expense (Benefit), Total	2,388	(102,080)	14,780
Deferred:
State	(113)	(3,226)	(22,673)
Deferred Income Tax Expense (Benefit), Total	76,881	19,110	(201,611)
Total income tax expense (benefit)	79,269	(82,970)	(186,831)
U.S. Drilling
Deferred:
U.S. federal	37,476	49,020	(164,297)
Outside the U.S
Current:
Outside the U.S.	32,928	59,491	31,846
Deferred:
Outside the U.S.	$ 39,518	$ (26,684)	$ (14,641)