Income Taxes - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Operating Loss Carryforwards [Line Items]
Federal income tax rate		35.00%	35.00%	35.00%
Federal net operating loss carryforwards expiration period start		2020
Federal net operating loss carryforwards expiration period end		2033
State operating loss carryforwards expiration period start		2018
State net operating loss carryingforwards period end		2033
State net operating loss carryingforwards expiration year		2018
State net operating loss carryingforwards expiring in initial year		$ 700,000
Provisional decrease in federal income tax		17,300,000
Net adjustment to deferred income tax benefit		17,300,000
Unrecognized tax benefits due to uncertain tax positions		6,300,000	$ 6,300,000	$ 6,300,000
Unrecognized tax benefits which would effect effective tax rate if recognized		800,000
Accrued interest and penalties related to uncertain tax positions		0
Scenario Plan
Operating Loss Carryforwards [Line Items]
Federal income tax rate	21.00%
Domestic Tax Authority
Operating Loss Carryforwards [Line Items]
Federal Net operating loss carrying forward		316,000,000
State and Local Jurisdiction
Operating Loss Carryforwards [Line Items]
Federal Net operating loss carrying forward		$ 222,000,000
Foreign Jurisdiction | Earliest Tax Year
Operating Loss Carryforwards [Line Items]
Income tax year under examination		2006
Foreign Jurisdiction | Latest Tax Year
Operating Loss Carryforwards [Line Items]
Income tax year under examination		2016