Employee Benefit Plans (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Defined pension plan benefits [Member]
Components of net periodic benefit cost
Service cost – benefits earned during the year	$ 7	$ 12	$ 22	$ 36
Interest cost on projected benefit obligations	491	564	1,383	1,691
Expected return on plan assets	(678)	(797)	(2,057)	(2,392)
Amortization of prior service cost	0	0	0	0
Amortization of net loss	180	184	613	553
Settlement expense	46	0	793	0
Net periodic benefit cost (income)	46	(37)	754	(112)
Other postretirement benefits [Member]
Components of net periodic benefit cost
Service cost – benefits earned during the year	32	36	116	107
Interest cost on projected benefit obligations	60	74	192	221
Expected return on plan assets	0	0	0	0
Amortization of prior service cost	34	40	120	121
Amortization of net loss	0	0	0	0
Settlement expense	0	0	0	0
Net periodic benefit cost (income)	$ 126	$ 150	$ 428	$ 449