Employee Benefit Plans (Details) (USD $)	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Components of net periodic benefit cost [Abstract]
Contribution to pension plan	$ 400,000
Anticipated additional contributions for the remainder of the year	1,200,000
Pension Plan [Member]
Components of net periodic benefit cost [Abstract]
Service cost	190,000	164,000
Interest cost	336,000	357,000
Expected return on plan assets	(557,000)	(497,000)
Amortization of prior service cost	(1,000)	(1,000)
Amortization of Net Loss	223,000	192,000
Net periodic benefit cost	191,000	215,000
Postretirement Benefits [Member]
Components of net periodic benefit cost [Abstract]
Service cost	6,000	13,000
Interest cost	119,000	130,000
Expected return on plan assets	0	0
Amortization of prior service cost	25,000	(3,000)
Amortization of Net Loss	63,000	71,000
Net periodic benefit cost	$ 213,000	$ 211,000