Commitments - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Schedule Of Commitments And Contingencies [Line Items]
Rent Expense	$ 947	$ 1,012	$ 939
Hannibal, Missouri
Schedule Of Commitments And Contingencies [Line Items]
Long Term Ground Leases Expiration Period		20 years	20 years
Marsing
Schedule Of Commitments And Contingencies [Line Items]
Long Term Ground Leases Expiration Period		25 years	25 years
Vehicle Lease
Schedule Of Commitments And Contingencies [Line Items]
Rent Expense	$ 435	$ 442	$ 334
Minimum \| Axis, Alabama
Schedule Of Commitments And Contingencies [Line Items]
Long Term Ground Leases Expiration Period	20 years
Maximum \| Axis, Alabama
Schedule Of Commitments And Contingencies [Line Items]
Long Term Ground Leases Expiration Period	35 years