Common Equity - Additional Information (Detail) (USD $) In Millions, except Share data, unless otherwise specified	12 Months Ended
	Mar. 31, 2013
Class of Stock [Line Items]
Warrants to purchase company common stock	7,399,103
Exercise price of common stock warrant	2.23
Term of warrant	10 years
Weighted average expected life	10 years
Risk free interest rate	3.35%
Weighted average expected volatility rate	50.12%
Dividend yield rate	1.55%
Estimated fair value of warrant	$ 37.1
Change in ownership	An ownership change would occur if our "5-percent shareholders," as defined under Section 382, collectively increase their ownership by more than 50 percentage points over a rolling three-year period