Derivatives and Hedging (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Jul. 31, 2016	Jul. 31, 2015
Derivative fair values
Income tax expense (benefit) recognized related to derivative securities within other comprehensive income	$ 0.9	$ 0.8	$ 0.6
Stockholders' equity	(17.6)	384.4	114.5	$ 134.2
Interest Expense
Derivative fair values
Hedge amount to be reclassified	3.5
Accumulated other comprehensive income
Derivative fair values
Income tax expense (benefit) recognized related to derivative securities within other comprehensive income	0.9
Stockholders' equity	(15.6)	(18.0)	(20.3)	$ (22.7)
Treasury rate lock | Accumulated other comprehensive income
Derivative fair values
Stockholders' equity	(15.6)
Treasury rate lock | Designated as a hedge
Derivative fair values
Derivative notional amount						$ 300.0
Derivative securities					$ (34.4)
Reclassification out of Accumulated Other Comprehensive Income | Accumulated other comprehensive income
Derivative fair values
Interest expense	$ 3.3	$ 3.1	$ 3.0