Employee Benefit Plans - Summary of plan weighted average asset allocation by asset category along with target allocation for 2014 (Details) (Retirement Income Plan)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012
Defined Benefit Plan Disclosure [Line Items]
Percentage of Plan Assets	100.00%	100.00%
Target Allocation for 2014 total percentage	100.00%
Cash and Cash Equivalents
Defined Benefit Plan Disclosure [Line Items]
Percentage of Plan Assets	0.60%	0.20%
Target Allocation for 2014 minimum percentage	0.00%
Target Allocation for 2014 maximum percentage	5.00%
Debt Securities - Core Fixed Income
Defined Benefit Plan Disclosure [Line Items]
Percentage of Plan Assets	25.30%	20.20%
Target Allocation for 2014 minimum percentage	15.00%
Target Allocation for 2014 maximum percentage	50.00%
Tactical - Fund of Equity and Debt Securities
Defined Benefit Plan Disclosure [Line Items]
Percentage of Plan Assets		15.10%
Target Allocation for 2014 minimum percentage
Domestic Equity Securities
Defined Benefit Plan Disclosure [Line Items]
Percentage of Plan Assets	26.60%	15.20%
Target Allocation for 2014 minimum percentage	0.00%
Target Allocation for 2014 maximum percentage	30.00%
Global Equity Securities
Defined Benefit Plan Disclosure [Line Items]
Percentage of Plan Assets		16.00%
Target Allocation for 2014 minimum percentage
International Equity Securities
Defined Benefit Plan Disclosure [Line Items]
Percentage of Plan Assets	31.40%	15.10%
Target Allocation for 2014 minimum percentage	0.00%
Target Allocation for 2014 maximum percentage	30.00%
Real Estate
Defined Benefit Plan Disclosure [Line Items]
Percentage of Plan Assets	8.30%	9.20%
Target Allocation for 2014 minimum percentage	0.00%
Target Allocation for 2014 maximum percentage	20.00%
Real Return
Defined Benefit Plan Disclosure [Line Items]
Percentage of Plan Assets	7.80%	9.00%
Target Allocation for 2014 minimum percentage	0.00%
Target Allocation for 2014 maximum percentage	20.00%