Income Taxes 2 of 2 (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Mar. 31, 2015	Mar. 31, 2014	Mar. 31, 2013	Mar. 31, 2012
Deferred tax assets:
State and foreign net operating loss carryforwards	$ 6,283	$ 5,495
Employee benefit plans	21,641	13,221
Insurance reserves	5,661	6,185
Accrued vacation and incentive costs	3,516	3,516
Federal tax credit carryforwards	2,134	2,543
Equity compensation	2,496	2,468
Other	3,814	4,337
Valuation allowance	(1,977)	(2,361)		(53,325)
Deferred tax assets after valuation allowance	43,568	35,404
Deferred tax liabilities:
Property, plant, and equipment	(3,568)	(3,421)
Intangible assets	(5,949)	(6,556)
Total deferred tax liabilities	(9,517)	(9,977)
Net deferred tax assets (liabilities)	34,051	25,427
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Beginning balance	2,357	1,986	2,428
Additions for prior year tax positions	0	754	0
Additions for current year tax positions	0	828	334
Reductions for prior year tax positions	(198)	0	(702)
Settlements	(50)	0	(30)
Foreign currency translation	(276)	42	(44)
Lapses in statutes of limitation	0	(1,253)	0
Ending balance	$ 1,833	$ 2,357	$ 1,986