Goodwill and Intangible Assets - Amortization (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Jan. 31, 2019	Jan. 31, 2018	Jan. 31, 2019	Jan. 31, 2018
Intangible assets
Amortization expense	$ 18,301	$ 10,481	$ 53,262	$ 31,527
Depreciation and amortization expense
Intangible assets
Amortization expense	$ 18,300	$ 10,500	$ 53,300	$ 31,500