Consolidated Balance Sheets (Parenthetical) (USD $)	Mar. 31, 2012	Mar. 31, 2011
Consolidated Balance Sheets [Abstract]
Preferred stock, par value	$ 0.01	$ 0.01
Preferred stock, shares authorized	2,000,000	2,000,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, par value	$ 0.01	$ 0.01
Common stock, shares authorized	375,000,000	375,000,000
Common stock, shares issued	61,879,000	63,666,000
Common stock, shares outstanding	61,879,000	63,666,000