Retirement Plans (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Employees' Pension Plan [Member]
Net Periodic Benefit Cost [Line Items]
Service Cost	$ 353	$ 377	$ 1,058	$ 1,130
Interest Cost	402	298	1,203	896
Expected Return on Plan Assets	(808)	(722)	(2,423)	(2,167)
Amortization of Prior Service (Credit) Cost	(21)	(11)	(62)	(33)
Amortization of Net Loss	139	86	417	258
Net Periodic Benefit Cost	65	28	193	84
Contributions to Retirement Benefits Plans	3,000	0	3,000	0
Estimated Future Contributions in the Current Fiscal Year			0
Select Executive Retirement Plan [Member]
Net Periodic Benefit Cost [Line Items]
Service Cost	3	0	8	0
Interest Cost	61	55	182	164
Expected Return on Plan Assets	0	0	0	0
Amortization of Prior Service (Credit) Cost	15	18	44	54
Amortization of Net Loss	30	23	91	68
Net Periodic Benefit Cost	109	96	325	286
Contributions to Retirement Benefits Plans	70	119	344	356
Estimated Future Contributions in the Current Fiscal Year			115
Post-Retirement Benefit Plans [Member]
Net Periodic Benefit Cost [Line Items]
Service Cost	43	52	130	158
Interest Cost	144	49	361	221
Expected Return on Plan Assets	0	0	0	0
Amortization of Prior Service (Credit) Cost	(8)	(29)	(23)	(86)
Amortization of Net Loss	24	7	71	20
Net Periodic Benefit Cost	203	79	539	313
Contributions to Retirement Benefits Plans	$ 106	$ 72	231	$ 300
Estimated Future Contributions in the Current Fiscal Year			$ 77