Fair Value - Fair Value Measurements, Recurring and Nonrecurring (Detail) - Fair Value Measurements [Member] $ in Thousands	Dec. 31, 2016 USD ($)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Deferred Acquisition Cost, Carrying Amount	$ 789
Deferred Acquisition Cost, Fair Value	789
Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Deferred Acquisition Cost, Fair Value	0
Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Deferred Acquisition Cost, Fair Value	0
Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Deferred Acquisition Cost, Fair Value	$ 789