Strategic Transformation and Restructuring, Impairment and Other Asset Charges (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Sep. 30, 2020	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Restructuring Cost and Reserve [Line Items]
Workforce reductions at multiple sites		$ 0.0	$ 1.3	$ 1.1
Other restructuring charges		0.0	0.3	0.0
Total restructuring related charges		2.9	9.9	2.9
Asset impairment charges:
Airplane impairment charges		0.0	2.3	0.3
Goodwill impairment charges		0.0	1.6	0.0
Other impairment charges		0.2	0.5	0.0
Total asset impairment charges		0.2	4.4	0.3
Gain on sale of property and equipment, net:
Total gain on sale of property and equipment, net		(0.6)	(6.2)	0.3
Total gain on sale of property and equipment, net		(0.6)	(6.2)	0.0
Restructuring, impairment and other asset charges, net		2.5	8.1	3.2
Costs associated with closing Tacoma | Facility Closing
Restructuring Cost and Reserve [Line Items]
Business exit costs		1.6	0.9	0.0
Gain on sale of property and equipment, net:
Total gain on sale of property and equipment, net		(1.6)
Costs associated with closing Enid | Facility Closing
Restructuring Cost and Reserve [Line Items]
Business exit costs		0.7	2.5	0.0
Other restructuring charges		0.7
Costs associated with closing Mequon | Facility Closing
Restructuring Cost and Reserve [Line Items]
Business exit costs		0.6	3.3	0.0
Other restructuring charges		0.6
Gain on sale of property and equipment, net:
Total gain on sale of property and equipment, net			(4.7)
Costs associated with closing Albuquerque | Facility Closing
Restructuring Cost and Reserve [Line Items]
Business exit costs		0.0	1.3	0.0
Gain on sale of property and equipment, net:
Total gain on sale of property and equipment, net	$ (0.4)
Costs associated with closing AMM | Facility Closing
Restructuring Cost and Reserve [Line Items]
Business exit costs		0.0	0.3	1.3
Costs associated with exiting the wood pellet business | Facility Closing
Restructuring Cost and Reserve [Line Items]
Business exit costs		$ 0.0	$ 0.0	$ 0.5