Income Taxes - Additional Information (Details) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Taxes [Line Items]
Tax Cuts And Jobs Act Of 2017, Transition Tax For Accumulated Foreign Earnings, Liability	$ 0
Tax Cuts And Jobs Act Of 2017, Incomplete Accounting, Change In Tax Rate, Deferred Tax Asset, Provisional Income Tax Expense	251,510,000
Decrease in valuation allowance related to changes in the estimated tax benefit of federal and state operating losses of separate-return entities	5,266,000
Liability for unrecognized tax benefits	32,776,000	$ 24,066,000	$ 39,011,000
Increase in liability for unrecognized tax benefits	8,710,000
Accrued interest and penalties related to unrecognized tax benefits, net of federal tax benefits	4,195,000	$ 2,595,000
Domestic Tax Authority
Income Taxes [Line Items]
Net operating loss carryforwards	137,852,000
State
Income Taxes [Line Items]
Net operating loss carryforwards	445,554,000
Foreign Tax Authority
Income Taxes [Line Items]
Net operating loss carryforwards	$ 138,717,000