Income Taxes - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Income Taxes [Line Items]
Net operating losses carry forward expiration date	Dec. 31, 2033
Unrecognized tax benefits that would impact effective tax rate	$ 2,600,000	$ 2,200,000	$ 2,100,000
Gross amount of interest and penalties	300,000	100,000	$ 0
Accrued for potential payment of interest and penalties	900,000	$ 600,000
Minimum [Member]
Income Taxes [Line Items]
Gross unrecognized tax benefit change in next 12 months	0
Maximum [Member]
Income Taxes [Line Items]
Gross unrecognized tax benefit change in next 12 months	1,300,000
State and Local Jurisdiction [Member]
Income Taxes [Line Items]
Tax credit carryforwards	$ 10,800,000
Tax credit carryforwards, expiration year	2021
State tax credits carry forward expiration date	Dec. 31, 2021
Net operating loss carryforwards	$ 600,000
Net operating loss carryforwards, expiration year	2033
Federal [Member]
Income Taxes [Line Items]
Net operating loss carryforwards	$ 5,800,000
Net operating loss carryforwards, expiration year	2034