Goodwill and Other Intangible Assets - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2019	Mar. 31, 2018
Goodwill and Intangible Assets Disclosure [Abstract]
Amortization expense on intangible assets	$ 9,509	$ 8,249	$ 17,622	$ 14,930
Future amortization expense [Abstract]
Future amortization expense for the remainder 2019	19,565		19,565
Future amortization expense 2020	37,226		37,226
Future amortization expense 2021	35,753		35,753
Future amortization expense 2022	34,112		34,112
Future amortization expense 2023	$ 32,504		$ 32,504