Fair Value of Financial Instruments (Details 3) (USD $)	12 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Revolving credit facility
Interest Rate Risk
Outstanding debt	$ 477,500,000
Revolving credit facility | LIBOR option
Interest Rate Risk
Outstanding debt	461,500,000
Interest rate (as a percent)	3.21%
Revolving credit facility | Base Rate
Interest Rate Risk
Outstanding debt	16,000,000
Interest rate (as a percent)	5.25%
Interest Rate Risk | Variable Rate Debt
Interest Rate Risk
Change in interest rate that would result in a change of annual interest expense (as a percent)	0.125%
Change in annual interest expense	600,000
Interest rate swaps
Interest Rate Risk
Notional amount	8,500,000
Derivative Liabilities		$ 100,000
Reference rate for variable interest rate	three-month LIBOR