The amounts in accumulated other comprehensive income related to gains and losses that are not recognized immediately and are expected to be recognized as components of net periodic benefit cost over the next fiscal year that follows the most recent annual statement of financial position presented.

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 132R

-Paragraph 5

-Subparagraph s

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.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

-Number 158

-Paragraph 7

-Subparagraph d

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.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 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 715

-SubTopic 20

-Section 50

-Paragraph 1

-Subparagraph (s)

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

Employee Benefits (Narrative) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Defined Benefit Plan Disclosure [Line Items]
Maximum employee contribution as a percentage of annual compensation	100.00%
Matching percentage by company of first 4% of employee contribution	100.00%
Percentage of employee contribution fully matched by company	4.00%
Length of service required to be eligible for annual retirement contributions (in years)	1
Number of subsidiaries company provides post-retirement healthcare benefits to	2
Length of time amendment increases pension plan (in years)	3
Return on asset assumption	7.00%
Percentage of investments for long-term growth included in investment strategy	65.00%
Percentage of investments for short-term growth included in investment strategy	35.00%
Discretionary range for pension fund trustee included in investment policy	10.00%
Equity securities, target allocation percentage	55.00%
Fixed income, target allocation percentage	45.00%
Matching Of Employee Contribution [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined contribution savings plan expense	$ 4,801	$ 4,556	$ 4,450
Annual Retirement Contribution [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined contribution savings plan expense	5,234	5,209	5,173
Salaried Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Expected 2011 contributions	2,862
Wage Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Expected 2011 contributions	1,923
Defined Benefit Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Estimated prior service cost to be amortized from other comprehensive income into net periodic benefit cost during 2012	297
Estimated net loss to be amortized from other comprehensive income into net periodic benefit cost during 2012	1,755
Post-Retirement Healthcare Benefit Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Estimated transition obligation to be amortized from other comprehensive income into net periodic benefit cost during 2012	0
Estimated prior service cost to be amortized from other comprehensive income into net periodic benefit cost during 2012	84
Estimated net loss to be amortized from other comprehensive income into net periodic benefit cost during 2012	$ (176)
Return on asset assumption
Minimum [Member]
Defined Benefit Plan Disclosure [Line Items]
Funded status of pension plans	61.00%
Maximum [Member]
Defined Benefit Plan Disclosure [Line Items]
Funded status of pension plans	80.00%