Shareholders' Equity - Share Repurchase and Dividends (Details) - USD ($) $ in Millions	1 Months Ended	3 Months Ended	9 Months Ended
	May 31, 2021	Sep. 30, 2021	Sep. 30, 2021	May 31, 2019
Shareholders' Equity
Number of shares purchased for issuance under share-based payment arrangement.		0
May 2019 Repurchase Program
Shareholders' Equity
Amount approved for repurchase of common stock				$ 300.0
Common stock repurchased during the period (in shares)			555,602
Aggregate cost of common stock repurchased during the period			$ 34.5
May 2021 Repurchase Program
Shareholders' Equity
Amount approved for repurchase of common stock	$ 500.0
Common stock repurchased during the period (in shares)			530,703
Aggregate cost of common stock repurchased during the period			$ 36.6
Remaining authorization amount for repurchase of common stock		$ 463.4	$ 463.4
Stock repurchase program,Purchase of common stock from time to time, period	2 years