Revolving Line of Credit and Long-Term Debt (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Jun. 30, 2012	Oct. 31, 2008
Revolving Line of Credit and Long-Term Debt
Maximum borrowing capacity		$ 19.5
Revolving Line of Credit
Revolving Line of Credit and Long-Term Debt
Maximum borrowing capacity		12.0
Term of debt instrument	2 years
Interest rate at the end of the period	3.25%
Monthly interest rate basis	prime
Unused line fee (as a percent)	0.25%
Revolving Line of Credit | Maximum
Revolving Line of Credit and Long-Term Debt
Basis points added to reference rate (as a percent)	0.50%
Bank Term Note
Revolving Line of Credit and Long-Term Debt
Term of debt instrument	48 months
Principal amount		$ 7.5