Consolidated Statements of Changes in Shareholders' Equity (Parenthetical) (USD $)	12 Months Ended
Mar. 31, 2011	Mar. 31, 2010	Mar. 31, 2009
Consolidated Statements of Changes in Shareholders' Equity
Series B 6.75% convertible perpetual preferred stock, per share	$ 67.5	$ 67.5	$ 67.5
Common stock, per share	$ 1.9	$ 1.86	$ 1.82

Aggregate dividends declared during the period for each share of common stock outstanding.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 04
-Article 3

Name:	us-gaap_CommonStockDividendsPerShareDeclared
Namespace Prefix:	us-gaap
Data Type:	us-types:perShareItemType
Balance Type:	na
Period Type:	duration