Supplemental Financial Information (Details) (USD $)	12 Months Ended
	Mar. 31, 2012	Mar. 31, 2011	Mar. 31, 2010
Supplemental Cash Flow Information [Abstract]
Cash paid for income taxes	$ 20,100,000	$ 17,000,000	$ 9,800,000
Cash paid for interest on borrowings	24,400,000	24,400,000	24,400,000
Allowance for Doubtful Accounts [Member]
Movement in Valuation Allowances and Reserves [Roll Forward]
Balances at Beginning of Year	2,838,000	3,109,000	3,176,000
Charged to Cost and Expense	7,000	31,000	90,000
Deductions	(243,000)	(302,000)	(157,000)
Balance at End of Year	$ 2,602,000	$ 2,838,000	$ 3,109,000