Income Taxes - Narrative (Detail) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income Taxes [Line Items]
Loss carryforwards		$ 694,591
Tax credit carryforwards		71,409
Deferred tax assets, valuation allowance		631,914	$ 610,560
Unrecognized tax benefits, end of period	$ 119,818	140,309	137,929	$ 119,818	$ 116,070
Amount of unrecognized tax benefits that would impact the effective tax rate if recognized		63,200
Amount of unrecognized tax benefits that would impact the effective tax rate if recognized and increase the valuation allowance		77,100
Increase (decrease) in recognized interest and penalties related to unrecognized tax benefits		(2,100)	(1,600)	7,900
Accrued interest and penalties related to unrecognized tax benefits		22,700	24,800
Tax reconciliation related to accumulated foreign earnings, net of related valuation allowance change	$ 3,700	0	0	$ 3,709
Reasonably possible changes to unrecognized tax benefits related to settlement of tax audits and/or expiration of statutes of limitations within the next twelve months		31,300
Deferred tax liability, undistributed foreign earnings		12,000	11,900
Decrease of deferred tax liabilities from undistributed foreign earnings		100
Undistributed foreign U.S GAAP retained earnings not taxed		6,000,000
Federal and State Tax Authorities
Income Taxes [Line Items]
Deferred tax assets, valuation allowance		319,000	300,000
Foreign Tax Authorities
Income Taxes [Line Items]
Deferred tax assets, valuation allowance		$ 313,000	$ 311,000