Interest Rates and Company Borrowings (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Interest and debt expense:
Weighted average interest rate during the period	1.69%	1.65%	1.71%	1.68%
Interest rate at the end of the period		1.72%		1.72%
Maximum amount outstanding during the quarter	$ 48,920	$ 38,599	$ 48,920	$ 38,599
Average amount outstanding during the period	26,374	21,717	25,154	18,049
Facility fees	$ 106	$ 100	$ 284	$ 307