Fair Value - Nonrecurring Fair Value Measurements (Details) - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020
Fair Value, Assets Measured on Recurring or Nonrecurring Basis
Assets held for sale	$ 0.7	$ 18.8
Right-of-use lease asset weighted average discount rate	3.30%	3.80%
Non FTFM shutdown assets held for sale		$ 17.2
Nonrecurring fair value measurement
Fair Value, Assets Measured on Recurring or Nonrecurring Basis
Right-of-use lease asset weighted average discount rate		4.10%
Nonrecurring fair value measurement | Level 2
Fair Value, Assets Measured on Recurring or Nonrecurring Basis
Fair value of assets held for sale		$ 1.8
Nonrecurring fair value measurement | Level 3
Fair Value, Assets Measured on Recurring or Nonrecurring Basis
Fair value of right-of-use lease assets		1.0
FTFM service offering shutdown
Fair Value, Assets Measured on Recurring or Nonrecurring Basis
Assets held for sale		$ 1.6
FTFM service offering shutdown | Nonrecurring fair value measurement
Fair Value, Assets Measured on Recurring or Nonrecurring Basis
Right-of-use lease asset weighted average discount rate		4.00%
FTFM service offering shutdown | Nonrecurring fair value measurement | Minimum
Fair Value, Assets Measured on Recurring or Nonrecurring Basis
Right-of-use lease asset discount rate		3.60%
FTFM service offering shutdown | Nonrecurring fair value measurement | Maximum
Fair Value, Assets Measured on Recurring or Nonrecurring Basis
Right-of-use lease asset discount rate		4.00%
FTFM service offering shutdown | Nonrecurring fair value measurement | Level 2
Fair Value, Assets Measured on Recurring or Nonrecurring Basis
Fair value of assets held for sale		$ 1.4
FTFM service offering shutdown | Nonrecurring fair value measurement | Level 3
Fair Value, Assets Measured on Recurring or Nonrecurring Basis
Fair value of right-of-use lease assets		$ 0.0