Benefit Plans - Additional Information (Detail)	3 Months Ended		9 Months Ended
	Sep. 30, 2016 USD ($)	Sep. 30, 2015 USD ($)	Sep. 30, 2016 USD ($) Employee	Sep. 30, 2015 USD ($)
Defined Benefit Plan Disclosure [Line Items]
Pension benefit costs | $	$ 0	$ (26,000)	$ 0	$ 76,000
Defined Benefit Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Matching contribution by the company to the plan			100.00%
Percentage of employees' eligible compensation			6.00%
Company contribution to defined benefit plan recorded as compensation expense | $	$ 100,000	$ 200,000	$ 500,000	$ 700,000
Number of employees covered under defined benefit pension plan			28
Defined Benefit Pension Plan [Member] | Retired Employee [Member]
Defined Benefit Plan Disclosure [Line Items]
Number of employees covered under defined benefit pension plan			2
Defined Benefit Pension Plan [Member] | Deferred Vested Termination [Member]
Defined Benefit Plan Disclosure [Line Items]
Number of employees covered under defined benefit pension plan			4
Defined Benefit Pension Plan [Member] | Survivor [Member]
Defined Benefit Plan Disclosure [Line Items]
Number of employees covered under defined benefit pension plan			1