Changes in Accumulated Other Comprehensive Loss - Changes in Accumulated Other Comprehensive Loss by Component (Detail) - USD ($) $ in Thousands	3 Months Ended
	Jun. 30, 2024	Jun. 30, 2023
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	$ 105,566	$ 96,933
Other comprehensive income before reclassifications	(28)	(252)
Amounts reclassified from accumulated other comprehensive loss	150	164
Total other comprehensive income (loss)	122	(88)
Ending Balance	108,188	99,721
Pension and Other Postretirement Benefits Items [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	(6,776)	(7,470)
Other comprehensive income before reclassifications	0	0
Amounts reclassified from accumulated other comprehensive loss	150	164
Total other comprehensive income (loss)	150	164
Ending Balance	(6,626)	(7,306)
Foreign Currency Items [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	(237)	7
Other comprehensive income before reclassifications	(28)	(252)
Amounts reclassified from accumulated other comprehensive loss	0	0
Total other comprehensive income (loss)	(28)	(252)
Ending Balance	(265)	(245)
Accumulated Other Comprehensive Loss [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	(7,013)	(7,463)
Ending Balance	$ (6,891)	$ (7,551)