Insurance Activity - Components of Liability for Losses and Loss Adjustment Reserves (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Effects of Reinsurance [Line Items]
Total losses and loss adjustment reserves	$ 18,947	$ 44,314	$ 82,524	$ 142,119
Case-basis reserves [Member]
Effects of Reinsurance [Line Items]
Total losses and loss adjustment reserves	16,538	41,159
IBNR reserves [Member]
Effects of Reinsurance [Line Items]
Total losses and loss adjustment reserves	110	713
Premium deficiency reserves [Member]
Effects of Reinsurance [Line Items]
Total losses and loss adjustment reserves	$ 2,299	$ 2,442