Employee Benefit Plans Employee Benefit Plans (Net benefit costs) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 137	$ 14,175
Interest cost	27,751	26,669
Supplemental Executive Retirement Plan
Defined Benefit Plan Disclosure [Line Items]
Service cost	294	282	$ 586
Interest cost	1,775	2,122	2,528
Amortization of unrecognized prior service cost	501	933	4,844
Amortization of loss from earlier periods	(61)	663	282
Settlement	0	0	1,857
Net periodic cost	2,509	4,000	10,097
Post-Retirement Medical Plan
Defined Benefit Plan Disclosure [Line Items]
Service cost	1,246	1,042	985
Interest cost	713	560	574
Amortization of unrecognized prior service cost	(1,102)	(1,640)	(1,706)
Amortization of loss from earlier periods	(317)	(511)	(450)
Net periodic cost	540	(549)	(597)
Defined Benefit Pension Plan
Defined Benefit Plan Disclosure [Line Items]
Service cost	(1,403)	12,851	4,952
Interest cost	25,263	23,987	23,068
Expected return on plan assets	(22,339)	(28,345)	(29,288)
Amortization of unrecognized prior service cost	0	13	51
Amortization of loss from earlier periods	10,260	12,398	2,898
Net periodic cost	$ 11,781	$ 20,904	$ 1,681