Income Taxes - Additional Information (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Current tax liability	$ 1,434	$ 1,023
Federal net operating loss	85,684
Capital losses in excess of capital gains	58,892
Unrecognized tax benefit	1,231	1,231	1,231
Interest expense related to current income taxes	79	92	0
Accrued interest in current taxes payable	$ 171	$ 92