Income Taxes - Expiration of Loss and Tax Credit Carryforwards (Detail) $ in Thousands	Dec. 31, 2019 USD ($)
Operating Loss and Tax Credit Carryforward [Line Items]
Loss Carryforwards	$ 672,104
Tax Credit Carryforwards	52,558
Period of Expiration 2020 - 2024
Operating Loss and Tax Credit Carryforward [Line Items]
Loss Carryforwards	40,890
Tax Credit Carryforwards	456
Thereafter
Operating Loss and Tax Credit Carryforward [Line Items]
Loss Carryforwards	187,120
Tax Credit Carryforwards	31,809
No expiration date
Operating Loss and Tax Credit Carryforward [Line Items]
Loss Carryforwards	444,094
Tax Credit Carryforwards	$ 20,293