Employee Benefit Plans (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Mar. 31, 2021	Mar. 31, 2020
Retirement Benefits [Abstract]
Service cost	$ 287	$ 259	$ 571	$ 520
Interest cost	80	68	159	136
Expected return on plan assets	(87)	(29)	(174)	(59)
Amortization of actuarial losses	110	235	374	471
Pension expense for defined benefit plans	$ 390	$ 533	$ 930	$ 1,068