Defined Benefit Pension and Other Postretirement Benefit Plans (Details) $ in Thousands	3 Months Ended			6 Months Ended		12 Months Ended
	Sep. 30, 2017 USD ($)	Sep. 30, 2016 USD ($)	Jun. 30, 2015 USD ($)	Sep. 30, 2017 USD ($) plan	Sep. 30, 2016 USD ($)	Mar. 31, 2018 USD ($)
Pension
Defined Benefit Plan Disclosure
Contribution by employer				$ 500
Net periodic benefit (income) costs
Net service cost	$ 1,316	$ 347	$ 693		$ 2,632
Interest cost	425	358	717		850
Expected return on net assets	(504)	(94)	(188)		(1,007)
Amortization:
Defined Benefit Plan, Actuarial Gain (Loss)	20	115	230		40
Prior service cost	90	21	42		181
Total net periodic benefit (income) costs	1,347	747	1,494		2,696
Pension | Europe
Defined Benefit Plan Disclosure
Defined Benefit Plan, Number of Plans | plan				6
Pension | Singapore
Defined Benefit Plan Disclosure
Defined Benefit Plan, Number of Plans | plan				1
Pension | Mexico
Defined Benefit Plan Disclosure
Defined Benefit Plan, Number of Plans | plan				2
Pension | JAPAN
Defined Benefit Plan Disclosure
Defined Benefit Plan, Number of Plans | plan				1
Post-retirement Benefit Plan
Net periodic benefit (income) costs
Net service cost	0	0	0		0
Interest cost	3	4	8		6
Expected return on net assets	0	0	0		0
Amortization:
Defined Benefit Plan, Actuarial Gain (Loss)	(47)	(43)	(85)		(94)
Prior service cost	0	0	0		0
Total net periodic benefit (income) costs	$ (44)	$ (39)	$ (77)		$ (88)
Subsequent Event [Member] | Pension | Maximum
Defined Benefit Plan Disclosure
Estimated employer contribution in current fiscal year						$ 3,300