Comprehensive Income/Loss (Comprised of the following Components) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	$ 18,169	$ (1,173)
Net change in other comprehensive income (loss)	31,559	8,054
Ending Balance	49,728	6,881
Unrealized Gain (Loss) on Securities
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	4,398	(5,947)
Net change in other comprehensive income (loss)	9,347	4,729
Ending Balance	13,745	(1,218)
Accumulated Gain (Loss), Net, Cash Flow Hedge, Parent [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	16,479	6,148
Net change in other comprehensive income (loss)	22,984	3,285
Ending Balance	39,463	9,433
Defined Benefit Postretirement Plans
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	(2,708)	(1,374)
Net change in other comprehensive income (loss)	(772)	40
Ending Balance	(3,480)	(1,334)
AOCI Attributable to Parent [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Net change in other comprehensive income (loss)	$ 31,559	$ 8,054