Pension Plans and Other Post Employment Benefit Plans Weighted Average Assumptions used to Determine Net Periodic Benefit Cost - Pension (Details)	4 Months Ended	8 Months Ended	12 Months Ended
	Dec. 31, 2017	Aug. 31, 2017	Dec. 31, 2019	Dec. 31, 2018
Defined Benefit Plan Disclosure [Line Items]
Expected long-term rate of return on plan assets	6.25%	8.00%
Pension Plan
Defined Benefit Plan Disclosure [Line Items]
Net Periodic Benefit, Discount Rate	3.42%	3.80%	4.19%	3.38%
Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Rate of Compensation Increase	3.80%	3.80%	2.84%	4.04%
Expected long-term rate of return on plan assets	6.24%	7.66%	6.24%	6.19%
Pension Plan | Principal U.S. Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Net Periodic Benefit, Discount Rate	3.73%	4.16%	4.32%	3.65%
Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Rate of Compensation Increase	3.95%	3.95%	0.00%	4.25%
Expected long-term rate of return on plan assets	6.25%	8.00%	6.25%	6.25%