Employee Benefit Plans - Summary of plan weighted average asset allocation by asset category along with target allocation for 2014 (Details 6) (Retirement Income Plan)	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013
Defined Benefit Plan Disclosure [Line Items]
Target Allocation for 2015 total percentage	100.00%
Percentage of Plan Assets	100.00%	100.00%
Cash and Cash Equivalents
Defined Benefit Plan Disclosure [Line Items]
Target Allocation for 2015 minimum percentage	0.00%
Target Allocation for 2015 maximum percentage	5.00%
Percentage of Plan Assets	1.00%	0.60%
Debt Securities - Core Fixed Income
Defined Benefit Plan Disclosure [Line Items]
Target Allocation for 2015 minimum percentage	15.00%
Target Allocation for 2015 maximum percentage	50.00%
Percentage of Plan Assets	24.30%	25.30%
Domestic Equity Securities
Defined Benefit Plan Disclosure [Line Items]
Target Allocation for 2015 minimum percentage	0.00%
Target Allocation for 2015 maximum percentage	40.00%
Percentage of Plan Assets	37.00%	26.60%
International Equity Securities
Defined Benefit Plan Disclosure [Line Items]
Target Allocation for 2015 minimum percentage	0.00%
Target Allocation for 2015 maximum percentage	30.00%
Percentage of Plan Assets	22.80%	31.40%
Real Estate
Defined Benefit Plan Disclosure [Line Items]
Target Allocation for 2015 minimum percentage	0.00%
Target Allocation for 2015 maximum percentage	20.00%
Percentage of Plan Assets	10.50%	8.30%
Real Return
Defined Benefit Plan Disclosure [Line Items]
Target Allocation for 2015 minimum percentage	0.00%
Target Allocation for 2015 maximum percentage	20.00%
Percentage of Plan Assets	1.60%	7.80%
Alternative/Opportunistic/Special funds
Defined Benefit Plan Disclosure [Line Items]
Target Allocation for 2015 minimum percentage	0.00%
Target Allocation for 2015 maximum percentage	20.00%
Percentage of Plan Assets	2.80%

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Target allocation of investments of this type to total plan assets presented on a weighted average basis.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 715

-SubTopic 20

-Section 50

-Paragraph 1

-Subparagraph (d)(i)

-URI http://asc.fasb.org/extlink&oid=35743120&loc=d3e1928-114920

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 715

-SubTopic 20

-Section 50

-Paragraph 5

-Subparagraph (c)(i)

-URI http://asc.fasb.org/extlink&oid=35743120&loc=d3e2446-114920

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Target allocation maximum percentage of investments of this type to total plan assets presented on a weighted average basis.

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Target allocation minimum percentage of investments of this type to total plan assets presented on a weighted average basis.

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Percentage of fair value of investments (categorized by debt securities, equity securities, real estate and other plan assets) to the fair value of plan assets held.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 715

-SubTopic 20

-Section 50

-Paragraph 5

-Subparagraph (c)

-URI http://asc.fasb.org/extlink&oid=35743120&loc=d3e2446-114920

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 715

-SubTopic 20

-Section 50

-Paragraph 1

-Subparagraph (d)(1)

-URI http://asc.fasb.org/extlink&oid=35743120&loc=d3e1928-114920

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