Employee Benefit Plans Employee Benefit Plans (Amount recognized in consolidated balance sheet) (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Defined Benefit Plan Disclosure [Line Items]
Under funded status at December 31	$ (202,735)	$ (194,181)
Defined Benefit Pension Plan
Defined Benefit Plan Disclosure [Line Items]
Under funded status at December 31	(139,203)	(133,686)
Post-Retirement Medical Plan
Defined Benefit Plan Disclosure [Line Items]
Under funded status at December 31	(19,031)	(16,637)
Supplemental Executive Retirement Plan
Defined Benefit Plan Disclosure [Line Items]
Under funded status at December 31	(44,501)	(43,858)
Other liabilities
Defined Benefit Plan Disclosure [Line Items]
Under funded status at December 31	(202,735)	(194,181)
Other liabilities | Defined Benefit Pension Plan
Defined Benefit Plan Disclosure [Line Items]
Under funded status at December 31	(139,203)	(133,686)
Other liabilities | Post-Retirement Medical Plan
Defined Benefit Plan Disclosure [Line Items]
Under funded status at December 31	(19,031)	(16,637)
Other liabilities | Supplemental Executive Retirement Plan
Defined Benefit Plan Disclosure [Line Items]
Under funded status at December 31	(44,501)	(43,858)
Accumulated other comprehensive income (loss)
Defined Benefit Plan Disclosure [Line Items]
Under funded status at December 31	(129,700)	(131,666)
Accumulated other comprehensive income (loss) | Defined Benefit Pension Plan
Defined Benefit Plan Disclosure [Line Items]
Under funded status at December 31	(133,055)	(139,316)
Accumulated other comprehensive income (loss) | Post-Retirement Medical Plan
Defined Benefit Plan Disclosure [Line Items]
Under funded status at December 31	5,715	8,540
Accumulated other comprehensive income (loss) | Supplemental Executive Retirement Plan
Defined Benefit Plan Disclosure [Line Items]
Under funded status at December 31	$ (2,360)	$ (890)