Other Noncurrent Assets (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2014		Mar. 31, 2014
Other noncurrent assets
Deposits	$ 68,306	[1]	$ 4,040	[1]
Deferred financing costs	6,336		14,773
Investment in affiliates	671		549
Capitalized software, net	2,791		3,864
Retirement plans	18,637		14,941
Other	10,106		12,503
Total	$ 106,847		$ 50,670

[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.