Employee Benefit Plans Textual (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011
Defined Benefit Plan Disclosure [Line Items]
Expected 2013 amortization of pension prior service costs	323
Expected 2013 amortization of actuarial loss	1,942
Projected benefit obligation, pension plans with accumulated benefit obligations in excess of plan assets	5,893	5,425
Defined Benefit Plan, Pension Plans with Accumulated Benefit Obligations in Excess of Plan Assets, Aggregate Accumulated Benefit Obligation	5,893	5,425
Defined Benefit Plan, Pension Plans with Accumulated Benefit Obligations in Excess of Plan Assets, Aggregate Fair Value of Plan Assets	0	0
Effect of one percentage point increase on accumulated postretirement benefit obligation	259
Effect of one percentage point decrease on accumulated postretirement benefit obligation	235
Employer matching contribution, allowable matching percentage based on terms of the plan	100.00%
Employer matching contribution, percent	6.00%
Maximum annual contribution per employee, percent	4.00%
Fixed income securities
Defined Benefit Plan Disclosure [Line Items]
Company's Pension Plan Asset Allocation, Description	entirely	Entirely
Defined Benefit Plan, Target Plan Asset Allocations	100.00%
Corporate Bond Securities
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Actual Fixed Income Securities Allocations	75.00%	74.00%
US Treasury and Government
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Actual Fixed Income Securities Allocations	16.00%	16.00%
Agency Securities
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Actual Fixed Income Securities Allocations	6.00%	7.00%
Other fixed income securities
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Actual Fixed Income Securities Allocations	3.00%	3.00%
Minimum
Defined Benefit Plan Disclosure [Line Items]
Medical postretirement plans, qualifying retirement age range	62 years
Maximum
Defined Benefit Plan Disclosure [Line Items]
Medical postretirement plans, qualifying retirement age range	65 years