Benefit Plans (Details 5) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2011
Pension Plans [Member]
Estimated Future Benefit Payments
2012	$ 42,048
2013	41,488
2014	50,147
2015	48,123
2016	50,085
2017-2021	275,298
Postretirement Plans [Member]
Estimated Future Benefit Payments
2012	9,966
2013	10,344
2014	10,783
2015	11,048
2016	11,379
2017-2021	$ 61,962

The amount of the aggregate benefits expected to be paid in the five fiscal years thereafter (the aggregate amount of benefits expected to be paid in years 6 through 10 after the date of the latest statement of financial position).

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 132R

-Paragraph 5

-Subparagraph f

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 715

-SubTopic 20

-Section 50

-Paragraph 1

-Subparagraph (f)

-URI http://asc.fasb.org/extlink&oid=6962843&loc=d3e1928-114920

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant