Share-Based Payments - Shares Issued Under Employee Stock Purchase Plan (Details) - USD ($) shares in Thousands, $ in Millions	1 Months Ended	12 Months Ended
	Jun. 30, 2015	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Employee Stock Ownership Plan (ESOP) Disclosures [Line Items]
Shares issued under the 2015 ESPP (in shares)	6,200
2015 ESPP
Employee Stock Ownership Plan (ESOP) Disclosures [Line Items]
Shares issued under the 2015 ESPP (in shares)		248	212	204
Cash received under the 2015 ESPP		$ 54.4	$ 48.6	$ 40.4