Employee Benefit Plans (Expected Benefit Payments) (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012
Qualified Pension Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
2013	$ 53,386
2014	57,240
2015	61,505
2016	65,900
2017	70,729
2018-2022	428,158
Non-Qualified Pension Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
2013	5,135
2014	5,144
2015	5,120
2016	5,154
2017	5,211
2018-2022	25,783
Postretirement Medical Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
2013	6,588
2014	6,822
2015	7,136
2016	7,618
2017	7,969
2018-2022	$ 41,564