Income Taxes - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 01, 2016
Income Tax Disclosure [Abstract]
Unrecognized Tax Benefits, Income Tax Penalties Expense, Increase		$ 20
Unrecognized Tax Benefits, Income Tax Penalties Expense			$ 200
Tax Cuts And Jobs Act Of 2017, Incomplete Accounting, Change In Tax Rate, Deferred Tax Asset, Provisional Income Tax Expense	$ 14,000	14,000
Unrecognized Tax Benefits	$ 0	$ 0	$ 1,315
Effective Income Tax Rate Reconciliation, Change in Enacted Tax Rate, Percent	22.90%	22.90%	0.00%	0.00%
Unrecognized Tax Benefits that Would Impact Effective Tax Rate			$ 1,300		$ 3,400