Income Taxes - Additional Information (Detail) - USD ($)	3 Months Ended
	Mar. 31, 2017	Dec. 31, 2016
Operating Loss Carryforwards [Line Items]
Other deferred tax assets, net	$ 43,700,000	$ 43,100,000
Alternative minimum tax credit carryforward	$ 6,800,000
Earliest Tax Year [Member]
Operating Loss Carryforwards [Line Items]
Tax years open for examination	2013
Latest Tax Year [Member]
Operating Loss Carryforwards [Line Items]
Tax years open for examination	2016
Le Mars [Member]
Operating Loss Carryforwards [Line Items]
Valuation allowance related to the portion of operating loss carryforwards	$ 440,778
Operating loss carryforwards	$ 2,000,000
Operating loss carryforwards expiration period	2020
Operating loss carryforwards annual limitations in amount on use	$ 376,000