Preferred Stock - Additional Information (Detail) (USD $)	12 Months Ended
	Mar. 31, 2013	Mar. 31, 2012	Mar. 31, 2011
Class of Stock [Line Items]
Number of preferred stock authorized to issue	5,000,000	5,000,000
Preferred stock par value	$ 0.10	$ 0.10
Amount received on capital purchase plan	$ 110,000,000
Warrants to purchase company common stock	7,399,103
Preferred stock dividends in arrears	6,560,000	6,278,000	5,934,000
Preferred stock redemption price	$ 1,000
Preferred stock accretion of discount period	5 years
Fifth Anniversary
Class of Stock [Line Items]
Preferred stock dividend rate percentage	5.00%
After Five Years and Thereafter
Class of Stock [Line Items]
Preferred stock dividend rate percentage	9.00%
Series B Preferred Stock
Class of Stock [Line Items]
Number of deferred dividend payments on series B Preferred Stock	16
Preferred Stock
Class of Stock [Line Items]
Amount received on capital purchase plan	72,900,000
Preferred stock dividends in arrears	25,300,000	18,800,000
Warrant
Class of Stock [Line Items]
Amount received on capital purchase plan	$ 37,100,000