Employee Benefit Plans (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Defined pension plan benefits
Components of net periodic benefit cost
Service (benefit) cost – benefits earned during the year	$ (2)	$ 25	$ 14	$ 32
Interest cost on projected benefit obligations	454	499	900	993
Expected return on plan assets	(532)	(694)	(1,075)	(1,407)
Amortization of prior service cost	0	0	0	0
Amortization of net loss	163	194	354	347
Net periodic benefit cost (income)	83	24	193	(35)
Other postretirement benefits
Components of net periodic benefit cost
Service (benefit) cost – benefits earned during the year	34	29	74	65
Interest cost on projected benefit obligations	60	62	126	135
Expected return on plan assets	0	0	0	0
Amortization of prior service cost	13	40	26	80
Amortization of net loss	0	0	0	0
Net periodic benefit cost (income)	$ 107	$ 131	$ 226	$ 280