Consolidated Balance Sheets (Parenthetical) (USD $)	Jun. 30, 2011	Mar. 31, 2011	Jun. 30, 2010
Common stock, no par value
Common stock, shares authorized	100,000,000	100,000,000	100,000,000
Common stock, shares issued	23,226,863	23,240,503	24,155,316
Common stock, shares outstanding	23,226,863	23,240,503	24,155,316
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