Retirement Plans, Weighted Average Assumptions Used to Determine Net Periodic Benefit Cost, Pension Benefits (Details)		2 Months Ended		3 Months Ended	9 Months Ended		12 Months Ended
		Mar. 31, 2018	Feb. 14, 2018	Apr. 11, 2017	Sep. 30, 2018	Dec. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Pension Benefits [Member]
Weighted average assumptions used to determine net periodic benefit cost [Abstract]
Discount rate	[1]			4.20%		4.00%	3.70%		4.50%
Expected long-term rate of return on plan assets							7.00%	7.00%	7.50%
Pension Benefits [Member] | Higman [Member]
Weighted average assumptions used to determine net periodic benefit cost [Abstract]
Discount rate	[1]	4.02%	4.13%		4.40%
SERP [Member]
Weighted average assumptions used to determine net periodic benefit cost [Abstract]
Discount rate	[1]						3.70%	4.20%	4.50%
Expected long-term rate of return on plan assets							0.00%	0.00%	0.00%
Rate of compensation increase							0.00%	0.00%	0.00%

[1] The 2018 discount rate for benefit cost for the Higman pension plan was changed from 4.13% as of February 14, 2018 and 4.02% as of March 31, 2018 to 4.40% as of December 31, 2018. In 2017, benefit cost for the pension plan was determined using a discount rate of 4.2% for the period beginning January 1, 2017 and ending April 11, 2017 and 4.0% for the period beginning April 12, 2017 and ending December 31, 2017.