Accumulated Other Comprehensive Loss (Details) - USD ($)	6 Months Ended	12 Months Ended
	Sep. 30, 2020	Mar. 31, 2020	Jun. 30, 2020	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019
Accumulated Other Comprehensive Income (Loss) [Line Items]
Shareholders' equity	$ 1,278,217,000	$ 1,170,971,000	$ 1,227,014,000	$ 1,112,790,000	$ 1,101,623,000	$ 1,095,831,000
Reclassification from accumulated other comprehensive loss into earnings	0	0
Cumulative translation adjustment
Accumulated Other Comprehensive Income (Loss) [Line Items]
Shareholders' equity	(24,986,000)	(39,241,000)
Unrealized loss on interest rate swaps, net of tax of $1,067 and $1,453, respectively
Accumulated Other Comprehensive Income (Loss) [Line Items]
Shareholders' equity	(3,570,000)	(4,864,000)
Other comprehensive income (loss), cash flow hedge, reclassification tax	1,067,000	1,453,000
Unrecognized net loss on pension plans, net of tax of $17 and $17, respectively
Accumulated Other Comprehensive Income (Loss) [Line Items]
Shareholders' equity	(56,000)	(56,000)
Accumulated other comprehensive income, accumulated tax	17,000	17,000
Accumulated other comprehensive loss, net of tax
Accumulated Other Comprehensive Income (Loss) [Line Items]
Shareholders' equity	$ (28,612,000)	$ (44,161,000)	$ (33,262,000)	$ (29,555,000)	$ (25,971,000)	$ (25,747,000)