Goodwill and Intangible Assets Goodwill, Changes in Carrying values (Details) - USD ($) $ in Thousands	6 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Goodwill [Line Items]
Document Period End Date	Mar. 31, 2019
Balance as of September 30, 2018	$ 3,247,105
Acquisitions		$ 6,800
Purchase accounting adjustments	(267)
Effect of foreign currency translation	(8,428)
Balance at March 31, 2019	3,238,410
Healthcare
Goodwill [Line Items]
Balance as of September 30, 2018	1,430,325
Purchase accounting adjustments	88
Effect of foreign currency translation	(2,448)
Balance at March 31, 2019	1,427,965
Enterprise
Goodwill [Line Items]
Balance as of September 30, 2018	683,347
Purchase accounting adjustments	0
Effect of foreign currency translation	(2,406)
Balance at March 31, 2019	680,941
Automotive
Goodwill [Line Items]
Balance as of September 30, 2018	1,119,947
Purchase accounting adjustments	(355)
Effect of foreign currency translation	(3,139)
Balance at March 31, 2019	1,116,453	$ 1,080,500
Other
Goodwill [Line Items]
Balance as of September 30, 2018	13,486
Purchase accounting adjustments	0
Effect of foreign currency translation	(435)
Balance at March 31, 2019	$ 13,051