Income Taxes - Summary of Estimated Loss and Tax Credit Carryforwards (Detail)	12 Months Ended
	Dec. 31, 2016 USD ($)
Tax Credit Carryforward [Line Items]
Federal net operating loss carryforward, Tax Effected	$ 14,534
State net operating loss carryforwards, Tax Effected	2,488
Federal [Member]
Tax Credit Carryforward [Line Items]
Federal general business credits, Tax Effected	2,674
Capital loss carryforwards, Tax Effected	$ 3,588
Federal net operating loss carryforward, Expiration	2036
Federal [Member] | Minimum [Member]
Tax Credit Carryforward [Line Items]
Federal general business credits, Expiration	2034
Capital loss carryforwards, Expiration	2019
Federal [Member] | Maximum [Member]
Tax Credit Carryforward [Line Items]
Federal general business credits, Expiration	2036
Capital loss carryforwards, Expiration	2020
State [Member]
Tax Credit Carryforward [Line Items]
Capital loss carryforwards, Tax Effected	$ 507
State [Member] | Minimum [Member]
Tax Credit Carryforward [Line Items]
Capital loss carryforwards, Expiration	2019
State net operating loss carryforwards, Expiration	2018
State [Member] | Maximum [Member]
Tax Credit Carryforward [Line Items]
Capital loss carryforwards, Expiration	2020
State net operating loss carryforwards, Expiration	2036