Income Taxes (Details) - USD ($)	3 Months Ended		6 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Mar. 31, 2020	Mar. 31, 2019
Effective tax rate	17.40%	18.50%	12.80%	16.90%
Income tax expense	$ 9,900,000	$ 11,200,000	$ 12,700,000	$ 18,600,000
Voalte [Member]
Business Combination, Contingent Consideration Arrangements, Change in Amount of Contingent Consideration, Liability	$ 8,400,000