Stock Compensation Plans - Options (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Options Outstanding Activity
Options outstanding, beginning of period (in shares)	5,927,398
Options granted (in shares)	0
Options exercised (in shares)	(329,824)
Options expired (in shares)	(315,118)
Options cancelled (in shares)	(217,641)
Options outstanding, end of period (in shares)	5,064,815	5,927,398
Weighted Average Exercise Price
Options outstanding, beginning of period (in dollars per share)	$ 17.2
Options granted (in dollars per share)	0
Options exercised (in dollars per share)	10.12
Options expired (in dollars per share)	15.69
Options cancelled (in dollars per share)	17.48
Options outstanding, end of period (in dollars per share)	$ 17.74	$ 17.2
Other Options Information
Options vested and expected to vest (in shares)	5,052,481
Options exercisable (in shares)	3,861,080
Options available for grant (in shares)	18,710,713
Options vested and expected to vest, weighted average exercise price (in dollars per share)	$ 17.76
Outstanding end of period (in dollars per share)	$ 20.12
Options outstanding, weighted average remaining contractual term	4 years 6 months
Options vested and expected to vest, weighted average remaining contractual term	4 years 6 months
Options exercisable, weighted average remaining contractual term	3 years 10 months 24 days
Options exercised, aggregate intrinsic value	$ 1.0	$ 0.4	$ 11.0
Options outstanding, aggregate intrinsic value	13.1
Options vested and expected to vest, aggregate intrinsic value	13.0
Options exercisable, aggregate intrinsic value	$ 8.0