Pension and Other Postretirement Plans (Details) (USD $)	3 Months Ended
	Mar. 31, 2015	Mar. 31, 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	$ 51,000	$ 42,000
Interest cost	246,000	240,000
Expected return on plan assets	(330,000)	(320,000)
Amortization of prior service cost	1,000	1,000
Amortization of net loss	196,000	105,000
Net periodic benefit cost	164,000	68,000
Minimum required contribution	0
Company contributions to plan	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	64,000	73,000
Interest cost	219,000	251,000
Amortization of prior service cost	15,000	15,000
Amortization of net loss	378,000	323,000
Net periodic benefit cost	676,000	662,000
Company contributions to plan	400,000
Company expected contributions to plans in fiscal year	2,000,000
Defined Benefit Postretirement Healthcare Plans [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Interest cost	32,000	28,000
Amortization of prior service cost	26,000	26,000
Amortization of net loss	15,000	(1,000)
Net periodic benefit cost	$ 73,000	$ 53,000
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%