Subsequent Events - Additional Information (Detail) (USD $)	1 Months Ended	12 Months Ended					1 Months Ended
	Jan. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Feb. 01, 2013	Oct. 31, 2012	Feb. 01, 2013 Zena Energy [Member]	Jan. 31, 2013 Dividend Declared [Member]
Subsequent Event [Line Items]
Dividends on Preferred Stock		$ 300,000	$ 305,000	$ 305,000				$ 300,000
Approved insurance payments with insurance carriers reservation of rights	20,000,000
Retoractive tax relief		450,000
Original principal amount			26,900,000	2,500,000	35,000,000
Purchase price of business acquisition						$ 50,000,000
Zena acquisition term loan interest rate basis							Interest is payable monthly based on a five-year amortization at a defined LIBOR rate plus 300 basis points (but not below 3.00% per annum)
Zena acquisition term loan borrowing rate							3.30%