Income Taxes - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Investments, Owned, Federal Income Tax Note [Line Items]
Effective income tax rate reconciliation at federal statutory income tax rate		35.00%
Deferred Tax Assets, Operating Loss Carryforwards, State and Local		$ 1,200	$ 1,200
Deferred Tax Assets, Operating Loss Carryforwards, Domestic		53,000
Unrecognized Tax Benefits		495	10,625	$ 10,625
Unrecognized Tax Benefits, Income Tax Penalties and Interest Accrued		$ 300	$ 2,100
Operating Loss Carry forward Expiration Dates		expire beginning in 2018, if unused
Effective Income Tax Rate Reconciliation, Change in Enacted Tax Rate, Amount		$ 19,700
Scenario, Forecast [Member]
Investments, Owned, Federal Income Tax Note [Line Items]
Deferred Tax Assets, Tax Deferred Expense, Compensation and Benefits, Share-based Compensation Cost	$ 3,100
Scenario, Plan [Member]
Investments, Owned, Federal Income Tax Note [Line Items]
Effective income tax rate reconciliation at federal statutory income tax rate	21.00%
U.S. Federal
Investments, Owned, Federal Income Tax Note [Line Items]
Operating Loss Carry forward Expiration Dates		2015 and 2016
Indiana State
Investments, Owned, Federal Income Tax Note [Line Items]
Operating Loss Carry forward Expiration Dates		2014 through 2016