Retirement Benefit Plans - Net Periodic Pension Benefit (Details) - Defined Benefit Pension Plan - USD ($) $ in Thousands	4 Months Ended	12 Months Ended
	Mar. 31, 2017	Mar. 31, 2017
Defined Benefit Plan Disclosure [Line Items]
Interest cost	$ 32	$ 32
Expected return on plan assets		(42)
Net periodic pension benefit		$ (10)