Pension and Other Postretirement Benefits (Details 10) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012
Defined benefit pension plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Estimated future employer contributions in next fiscal year	$ 5,948
Defined Benefit Plan, Estimated Future Benefit Payments [Abstract]
2013	28,180
2014	28,566
2015	29,177
2016	29,710
2017	30,671
Years 2018-2022	155,697
Total	302,001
Other postretirement benefit plans [Member]
Defined Benefit Plan, Estimated Future Benefit Payments [Abstract]
2013	5,075
2014	4,924
2015	4,820
2016	4,646
2017	4,417
Years 2018-2022	18,821
Total	$ 42,703

The employer's best estimate, as soon as it can be reasonably determined, of contributions expected to be paid to the plan during the next fiscal year beginning after the date of the latest statement of financial position. Estimated contributions may be presented in the aggregate combining (1) contributions required by funding regulations or laws, (2) discretionary contributions, and (3) noncash contributions.

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 132R

-Paragraph 5

-Subparagraph g

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.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 (g)

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

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