Income Taxes - Income Tax Contingencies (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Income tax contingency disclosures
Unrecognized tax benefits: Changes due to lapses of statutes of limitations		$ 3,071	$ 19,465	$ 28,606
Accrued interest and penalties related to unrecognized tax benefits		200	600
Interest and penalties recorded		(400)	(800)	(1,200)
Forecast | Subsequent event
Income tax contingency disclosures
Unrecognized tax benefits: Changes due to lapses of statutes of limitations	$ 2,300
Additional Paid in Capital
Income tax contingency disclosures
Unrecognized tax benefits: Changes due to lapses of statutes of limitations			2,600	3,900
Deferred tax assets
Income tax contingency disclosures
Unrecognized tax benefits: Changes due to lapses of statutes of limitations		1,000
Deferred tax assets | Forecast | Subsequent event
Income tax contingency disclosures
Unrecognized tax benefits: Changes due to lapses of statutes of limitations	700
Income Tax Expense
Income tax contingency disclosures
Unrecognized tax benefits: Changes due to lapses of statutes of limitations		2,000	16,000	23,200
Interest expense related to unrecognized tax benefits		(400)	$ (1,400)	$ (2,100)
Income Tax Expense | Forecast | Subsequent event
Income tax contingency disclosures
Unrecognized tax benefits: Changes due to lapses of statutes of limitations	$ 1,500
Income Tax Expense | State
Income tax contingency disclosures
Unrecognized tax benefits: Changes due to lapses of statutes of limitations		$ 700