Pension and Other Post-retirement Benefit Plans (Details 2) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Mar. 31, 2013	Mar. 31, 2012	Mar. 31, 2011
Target allocation and weighted-average asset allocations
Target Allocation (as a percent)	100.00%
Plan Assets (as a percent)	100.00%
Estimated future pension benefit payments
Number of fiscal years	10 years
2014	$ 1,535
2015	1,540
2016	1,632
2017	1,740
2018	1,760
2019-2023	10,745
Pension
Other changes in plan assets and benefit obligations recognized in Accumulated other comprehensive income
Current year actuarial (gain) loss	3,669	2,845	2,918
Foreign currency exchange rate changes	(238)	(218)	728
Amortization of actuarial gain (loss)	(4,582)	(392)	(649)
Current year prior service cost			270
Amortization of prior service cost	(101)	(25)	(292)
Total recognized in other comprehensive income	(1,252)	2,210	2,975
Total recognized in net periodic benefit cost and other comprehensive income (loss)	2,408	5,336	5,633
Estimated future pension benefit payments
2014	1,444
2015	1,450
2016	1,546
2017	1,658
2018	1,683
2019-2023	10,450
Other Benefits
Other changes in plan assets and benefit obligations recognized in Accumulated other comprehensive income
Current year actuarial (gain) loss	(145)	(206)	(7)
Foreign currency exchange rate changes	322	323	306
Total recognized in other comprehensive income	177	117	299
Total recognized in net periodic benefit cost and other comprehensive income (loss)	(118)	(162)	55
Estimated future pension benefit payments
2014	91
2015	90
2016	86
2017	82
2018	77
2019-2023	$ 295
Insurance
Target allocation and weighted-average asset allocations
Target Allocation (as a percent)	10.00%
Plan Assets (as a percent)	7.00%
International equities
Target allocation and weighted-average asset allocations
Target Allocation (as a percent)	30.00%
Plan Assets (as a percent)	33.00%
International bonds
Target allocation and weighted-average asset allocations
Target Allocation (as a percent)	50.00%
Plan Assets (as a percent)	58.00%
Other
Target allocation and weighted-average asset allocations
Target Allocation (as a percent)	10.00%
Plan Assets (as a percent)	2.00%