Consolidated Balance Sheets (Parenthetical) (USD $)	Sep. 30, 2011	Mar. 31, 2011	Sep. 30, 2010
Common stock, no par value
Common stock, shares authorized	100,000,000	100,000,000	100,000,000
Common stock, shares issued	23,230,486	23,240,503	23,908,085
Common stock, shares outstanding	23,230,486	23,240,503	23,908,085
Series A Junior Participating Preferred Stock [Member]
Preferred stock, no par value
Preferred stock, shares authorized	500,000	500,000	500,000
Preferred stock, shares issued	0	0	0
Preferred stock, shares outstanding	0	0	0
Series B 6.75% Convertible Perpetual Preferred Stock [Member]
Preferred stock, no par value
Preferred stock, shares authorized	5,000,000	5,000,000	5,000,000
Preferred stock, shares issued	219,999	219,999	219,999
Preferred stock, shares outstanding	219,999	219,999	219,999