Income Taxes - Additional Information (Detail) (USD $)	6 Months Ended	12 Months Ended
	Jun. 30, 2013	Dec. 31, 2012
Operating Loss Carryforwards [Line Items]
Material unrealized tax benefits	$ 0	$ 0
Deferred tax asset, net	38,100,000	37,600,000
Operating loss carryforwards	2,200,000
Operating loss carryforwards expiration period	2031
Alternative minimum tax credit carryforward	8,000,000
Le Mars [Member]
Operating Loss Carryforwards [Line Items]
Valuation allowance related to the portion of operating loss carryforwards	440,778
Operating loss carryforwards	4,700,000
Operating loss carryforwards expiration period	2020
Operating loss carryforwards annual limitations in amount on use	$ 376,000