Income Taxes - Effective Income Tax Reconciliation (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Reconciliation of Income Tax Expense:
Loss from continuing operations before provision for income taxes	$ 20,306	$ (39,034)	$ (18,021)	$ (30,617)	$ (76,048)	$ (92,486)	$ (190,861)	$ (198,405)	$ (67,366)	$ (557,800)	$ (734,875)
Expected tax provision (benefit)									(23,578)	(195,230)	(257,206)
State taxes, net of federal benefit									3,621	3,800	1,124
Foreign rate differential									21,346	47,402	39,335
Tax credits									(47,773)	(55,696)	(33,788)
Unbenefitted operating losses (gains)									14,837	226,169	241,037
Non-deductible expenses									24,749	5,817	18,756
Rate change									12,836	(1,224)	(1,826)
Tax attribute expiration									9,947	0	0
Other									680	(657)	(474)
Provision for income taxes	$ (7,453)	$ 503	$ 18,130	$ 5,485	$ (1,379)	$ 1,330	$ 30,131	$ 299	$ 16,665	$ 30,381	$ 6,958