Pension and Other Postretirement Plans (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014	Dec. 31, 2007
Defined Benefit Pension Plans [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Vesting percentage in accrued benefits from plan freeze					100.00%
Service cost	$ 51	$ 42	$ 102	$ 84
Interest cost	246	239	492	479
Expected return on plan assets	(330)	(319)	(660)	(639)
Amortization of prior service cost	1	1	2	2
Amortization of net loss	196	106	392	211
Net periodic benefit cost	164	69	328	137
Minimum required contribution	0		0
Company contributions to plan			0	0
Chairman and President Non-Qualified Defined Benefit Plans [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost	64	74	128	147
Interest cost	219	251	438	502
Amortization of prior service cost	15	14	30	29
Amortization of net loss	379	324	757	647
Net periodic benefit cost	677	663	1,353	1,325
Company contributions to plan			900
Company expected contributions to plans in fiscal year			2,000
Defined Benefit Postretirement Healthcare Plans [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Interest cost	33	27	65	55
Amortization of prior service cost	26	26	52	52
Amortization of net loss	15	(1)	30	(2)
Net periodic benefit cost	$ 74	$ 52	$ 147	$ 105
Minimum [Member] | Chairman and President Non-Qualified Defined Benefit Plans [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Aggregate average annual participant salary increase (as a percentage)			10.00%