Shareholders' Equity - RSU Activity (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Restricted stock, Shares Subject to Restriction
Outstanding at the end of the period (in shares)	654,470
Unvested restricted stock units
Restricted stock, Shares Subject to Restriction
Outstanding at the beginning of the period (in shares)	805,052
Granted (in shares)	218,223
Vested (in shares)	(336,310)
Forfeited (in shares)	(32,495)
Outstanding at the end of the period (in shares)	654,470	805,052
Restricted stock, Weighted Average Grant Date Fair Value
Outstanding at the beginning of the period (in dollars per share)	$ 39.63
Granted (in dollars per share)	78.03
Vested (in dollars per share)	37.26
Forfeited (in dollars per share)	43.90
Outstanding at the end of the period (in dollars per share)	$ 53.44	$ 39.63
Additional share-based compensation disclosures
Total fair value of shares vested	$ 27.1	$ 15.0	$ 7.9