Employee Retirement Plans (Accumulated Benefit Obligations, Amounts Recognized on Balance Sheets, and Reconciliation of AOCI) (Details) - USD ($)	1 Months Ended	12 Months Ended
	Oct. 31, 2017	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Pension and Other Postretirement Benefit Plans, Accumulated Other Comprehensive Income (Loss), before Tax
Amount arising during the period		$ (8,100,000)	$ (18,100,000)	$ 18,700,000
Impact of pension plan settlement charge included in net earnings (loss)		0	0	800,000
Lump sum payments	$ 8,400,000		21,400,000
Pension liabilities settled			23,300,000
Pension Benefits
Defined Benefit Plan, Amounts Recognized in Balance Sheet
Current liabilities		(1,800,000)	(1,700,000)
Noncurrent liabilities		(77,100,000)	(80,900,000)
Total amount recognized		(78,900,000)	(82,600,000)
Pension and Other Postretirement Benefit Plans, Accumulated Other Comprehensive Income (Loss), before Tax
Settlement charge		0	0	(800,000)
Amortization of amounts in accumulated other comprehensive income expected to be recognized as components of net periodic pension income		0
Pension Benefits | Restructuring Charges
Pension and Other Postretirement Benefit Plans, Accumulated Other Comprehensive Income (Loss), before Tax
Settlement charge			800,000
Pension Benefits | Actuarial Gain (Loss), net
Pension and Other Postretirement Benefit Plans, Accumulated Other Comprehensive Income (Loss), before Tax
Accumulated other comprehensive income (loss), before Tax, beginning balance		(33,300,000)	(15,200,000)
Amount arising during the period		(8,100,000)	(18,100,000)
Accumulated other comprehensive income (loss), before Tax, ending balance		$ (41,400,000)	$ (33,300,000)	$ (15,200,000)