Pension Plan (Details) - Pension plan assets by level within the fair value hierarchy (USD $) In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Defined Benefit Plan Disclosure [Line Items]
Fair Value, Pension plan assets, Total	$ 7,946	$ 7,077	$ 6,019
Equity And Index Funds [Member] | Fair Value, Inputs, Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value, Pension plan assets, Total	5,551
Equity And Index Funds [Member] | Fair Value, Inputs, Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value, Pension plan assets, Total
Equity And Index Funds [Member] | Fair Value, Inputs, Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value, Pension plan assets, Total
Equity And Index Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value, Pension plan assets, Total	5,551
Fixed Income Funds [Member] | Fair Value, Inputs, Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value, Pension plan assets, Total	2,395
Fixed Income Funds [Member] | Fair Value, Inputs, Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value, Pension plan assets, Total
Fixed Income Funds [Member] | Fair Value, Inputs, Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value, Pension plan assets, Total
Fixed Income Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value, Pension plan assets, Total	2,395
Fair Value, Inputs, Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value, Pension plan assets, Total	7,946
Fair Value, Inputs, Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value, Pension plan assets, Total
Fair Value, Inputs, Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value, Pension plan assets, Total