Other Noncurrent Assets (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2013		Mar. 31, 2012
Other noncurrent assets
Deposits	$ 3,885	[1]	$ 4,566	[1]
Deferred financing costs	16,080		20,326
Investment in affiliates	1,877		1,963
Capitalized software, net	3,993		2,003
Loan to affiliate	1,005		1,005
Retirement plans	17,655		7,474
Financial instruments	0		2,323
Other	6,554		5,857
Other noncurrent assets, total	$ 51,049		$ 45,517

[1] Deposits principally represent amounts held by beneficiaries as cash collateral for the Company’s contingent obligations with respect to certain environmental matters, workers' compensation insurance, and operating lease commitments.