Income Taxes - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Income Tax Disclosure [Line Items]
Cash paid for income taxes	$ 1,062	$ 858	$ 923
Deferred tax assets, valuation allowance	$ 1,466	1,507
Deferred tax assets, charitable carryforwards expiration period	2016
Net benefit resulting from adjustment for revaluation of state net operating loss carryforwards	$ 1,817	2,977
Charitable Contribution Carryforwards [Member]
Income Tax Disclosure [Line Items]
Deferred tax assets, valuation allowance	$ 900	$ 1,500
Minimum [Member]
Income Tax Disclosure [Line Items]
Year federal net operating loss carryforwards begin to expire	2029
Ownership shift due to the secondary offering	50.00%
Federal Tax Credit Carry Forwards [Member]
Income Tax Disclosure [Line Items]
Net operating loss carryforwards	$ 677,000
State Tax Credit Carry Forwards [Member]
Income Tax Disclosure [Line Items]
Net operating loss carryforwards	1,100,000
Deferred tax assets, valuation allowance	$ 600