Employee Benefit Plans - Schedule of Weighted Average Actuarial Assumptions (Details)	3 Months Ended	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2019	Dec. 31, 2018	Sep. 30, 2017
Pension
Defined Benefit Plan Disclosure [Line Items]
Discount rate	3.75%	3.49%	4.57%	4.00%
Rate of compensation increase	3.50%	3.50%	3.50%	3.50%
Discount rate	4.00%	4.57%	3.75%	3.875%
Discount rate-remeasurement		3.85%
Expected rate of return on plan assets	7.25%	7.00%	7.25%	7.50%
Rate of compensation increase	3.50%	3.50%	3.50%	3.50%
RIM
Defined Benefit Plan Disclosure [Line Items]
Discount rate	3.625%	3.33%	4.47%	3.875%
Rate of compensation increase	3.50%	3.50%	3.50%	3.50%
Discount rate	3.875%	4.47%	3.625%	3.625%
Rate of compensation increase	3.50%	3.50%	3.50%	3.50%
Post-retirement
Defined Benefit Plan Disclosure [Line Items]
Discount rate	3.625%	3.27%	4.41%	3.875%
Discount rate	3.875%	4.41%	3.625%	3.625%