Retirement and Compensation Plans Net periodic pension costs incurred by the plans (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
United States Pension Plan of US Entity [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Service Cost	$ 5,795	$ 5,892	$ 5,295
Defined Benefit Plan, Interest Cost	14,447	13,472	13,919
Defined Benefit Plan, Expected Return on Plan Assets	(17,865)	(17,563)	(17,504)
Defined Benefit Plan, Amortization of Prior Service Cost (Credit)	144	144	144
Defined Benefit Plan, Amortization of Gains (Losses)	9,432	10,464	6,087
Defined Benefit Plan, Recognized Net Gain (Loss) Due to Settlements	0	(7,998)	(6,306)
Defined Benefit Plan, Net Periodic Benefit Cost	11,953	20,407	14,247
Net periodic pension cost individual entity share	3,807	6,614	4,569
Defined Benefit Plan, Amortization of Net Prior Service Cost (Credit)	100
Defined Benefit Plan, Future Amortization of Gain (Loss)	10,100
Defined Benefit Plan, Estimated Future Employer Contributions in Next Fiscal Year	15,000
Multiemployer Plans, Minimum Contribution	4,800
Defined Benefit Plan, Expected Future Benefit Payments, Next Twelve Months	14,400
Defined Benefit Plan, Expected Future Benefit Payments, Year Two	16,800
Defined Benefit Plan, Expected Future Benefit Payments, Year Three	17,300
Defined Benefit Plan, Expected Future Benefit Payments, Year Four	19,600
Defined Benefit Plan, Expected Future Benefit Payments, Year Five	19,400
Defined Benefit Plan, Expected Future Benefit Payments, Five Fiscal Years Thereafter	115,400
Other Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Service Cost	335	435	269
Defined Benefit Plan, Interest Cost	966	1,000	1,077
Defined Benefit Plan, Expected Return on Plan Assets	0	0	0
Defined Benefit Plan, Amortization of Prior Service Cost (Credit)	(1)	(11)	(11)
Defined Benefit Plan, Amortization of Gains (Losses)	918	1,528	1,131
Defined Benefit Plan, Recognized Net Gain (Loss) Due to Settlements	0	0	0
Defined Benefit Plan, Net Periodic Benefit Cost	2,218	2,952	2,466
Net periodic pension cost individual entity share	1,260	$ 1,671	$ 1,372
Defined Benefit Plan, Future Amortization of Gain (Loss)	$ 1,200
Defined Benefit Plan, Estimated Future Employer Contributions in Next Fiscal Year, Description	1.9
Multiemployer Plans, Minimum Contribution	$ 900
Defined Benefit Plan, Expected Future Benefit Payments, Next Twelve Months	2,400
Defined Benefit Plan, Expected Future Benefit Payments, Year Two	2,500
Defined Benefit Plan, Expected Future Benefit Payments, Year Three	3,200
Defined Benefit Plan, Expected Future Benefit Payments, Year Four	2,600
Defined Benefit Plan, Expected Future Benefit Payments, Year Five	2,300
Defined Benefit Plan, Expected Future Benefit Payments, Five Fiscal Years Thereafter	$ 9,400