Acquisitions Acquisitions - Assets and Liabilities Acquired (Details) - USD ($) $ in Thousands	Dec. 07, 2018	Mar. 31, 2020	Mar. 31, 2019	Mar. 31, 2018
Business Acquisition [Line Items]
Goodwill		$ 663,936	$ 656,399	$ 352,805
Alpha
Business Acquisition [Line Items]
Accounts receivable	$ 115,467
Inventories	84,297
Other current assets	6,822
Other intangible assets	332,000
Property, plant and equipment	20,987
Other assets	9,005
Total assets acquired	568,578
Accounts payable	35,803
Accrued liabilities	41,918
Deferred income taxes	54,941
Other liabilities	12,642
Total liabilities assumed	145,304
Net assets acquired	423,274
Cash paid for net assets acquired	650,000
Shares issued in acquisition, value	93,268
Working capital adjustment	(766)
Consideration transferred	742,502
Goodwill	$ 319,228