Employee Benefit Plans (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
Defined pension plan benefits
Components of net periodic benefit cost
Service cost – benefits earned during the year	$ 16	$ 7
Interest cost on projected benefit obligations	446	494
Expected return on plan assets	(543)	(713)
Amortization of prior service cost	0	0
Amortization of net loss	191	153
Net periodic benefit cost (income)	110	(59)
Other postretirement benefits
Components of net periodic benefit cost
Service cost – benefits earned during the year	40	36
Interest cost on projected benefit obligations	66	73
Expected return on plan assets	0	0
Amortization of prior service cost	13	40
Amortization of net loss	0	0
Net periodic benefit cost (income)	$ 119	$ 149