Employee Benefit Plan (Details 1) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Pension Plan [Member]
Components of Net Period Benefit Cost
Service cost	$ 625	$ 772
Interest cost	768	669
Expected return on plan assets	(1,258)	(995)
Amortization of net retirement plan actuarial loss	225	505
Amortization of net retirement plan prior service cost (credit)	(31)	(31)
Amortization of net retirement plan transition liability	0	0
Net periodic benefit cost	329	920
SERP Plan [Member]
Components of Net Period Benefit Cost
Service cost	93	109
Interest cost	214	185
Expected return on plan assets	0	0
Amortization of net retirement plan actuarial loss	84	122
Amortization of net retirement plan prior service cost (credit)	41	41
Amortization of net retirement plan transition liability	0	0
Net periodic benefit cost	432	457
Life and Healthcare Plan [Member]
Components of Net Period Benefit Cost
Service cost	55	51
Interest cost	98	86
Expected return on plan assets	0	0
Amortization of net retirement plan actuarial loss	11	27
Amortization of net retirement plan prior service cost (credit)	4	4
Amortization of net retirement plan transition liability	0	13
Net periodic benefit cost	$ 168	$ 181