Summary of Significant Accounting Policies - Components of AOCI (Details) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2017
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance at beginning of year	$ 253,695	$ 294,154	$ 271,490
Balance at end of year	189,931	253,695	294,154
Accumulated effect of currency translation adjustment
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance at beginning of year	988	45	0
OCI, gain (loss)	(976)	943	45
Balance at end of year	12	988	45
Accumulated effect of pension and postretirement benefits
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance at beginning of year	259	(108)	(62)
OCI, gain (loss)	194	367	(46)
Balance at end of year	453	259	(108)
Accumulated effect interest rate swap agreement
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance at beginning of year	(84)	0	0
Amounts reclassified from accumulated other comprehensive income (loss)	84	0	0
OCI, gain (loss)	0	(84)	0
Balance at end of year	$ 0	$ (84)	$ 0