Income Taxes - Additional Information (Detail) - USD ($)	3 Months Ended
	Mar. 31, 2017	Dec. 31, 2016
Income Tax Disclosure [Abstract]
Net deferred tax asset	$ 14,464,000	$ 12,735,000
Operating loss carryforwards used against taxable income	$ 27,600,000
Expiration dates, operating loss carried forward	Dec. 31, 2030
Alternative minimum tax credits carried forward	$ 1,700,000