Defined Benefit Pension Plans (Components of Net Periodic Benefit Cost) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Qualified Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 537	$ 615	$ 1,611	$ 1,844
Interest cost	644	731	1,932	2,195
Expected return on plan assets	(1,158)	(1,129)	(3,475)	(3,386)
Amortization of prior service (credit) cost	(6)	(6)	(17)	(17)
Recognized net actuarial loss	207	313	621	937
Net periodic benefit cost	224	524	672	1,573
Non-Qualified Retirement Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	30	20	91	59
Interest cost	108	122	324	367
Expected return on plan assets	0	0	0	0
Amortization of prior service (credit) cost	0	0	0	0
Recognized net actuarial loss	62	61	185	183
Net periodic benefit cost	$ 200	$ 203	$ 600	$ 609