Significant Accounting Policies Property, Plant and Equipment (Details) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2016	Mar. 31, 2015	Mar. 31, 2014
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 421,535	$ 366,171
Less accumulated depreciation	(144,010)	(128,257)
Total property, plant and equipment, net	277,525	237,914
Property and equipment purchases	17,786	22,673	$ 27,755
Property and equipment purchases, amount unpaid	1,359	1,024	4,322
Land [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	26,995	21,564
Building [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	211,540	170,937
Machinery and Equipment [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	183,000	173,670
Cost of Sales [Member]
Property, Plant and Equipment [Line Items]
Depreciation expense	23,132	24,179	25,706
Operating Expense [Member]
Property, Plant and Equipment [Line Items]
Depreciation expense	$ 2,699	$ 2,998	$ 3,209
Minimum [Member] | Building [Member]
Property, Plant and Equipment [Line Items]
Useful life (in years)	20 years
Minimum [Member] | Machinery and Equipment [Member]
Property, Plant and Equipment [Line Items]
Useful life (in years)	3 years
Maximum [Member] | Building [Member]
Property, Plant and Equipment [Line Items]
Useful life (in years)	30 years
Maximum [Member] | Machinery and Equipment [Member]
Property, Plant and Equipment [Line Items]
Useful life (in years)	10 years