Other Comprehensive Income (Loss) (Components of Accumulated Other Comprehensive Income) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Accumulated other comprehensive income (loss), beginning balance	$ (11,866)	$ (35,062)	$ (28,309)	$ (23,510)
Other comprehensive income (loss) before reclassifications	2,669	(5,009)	18,614	(17,475)
Amounts reclassed from accumulated other comprehensive income (loss)	273	994	771	1,908
Total other comprehensive income (loss), net of tax	2,942	(4,015)	19,385	(15,567)
Accumulated other comprehensive income (loss), ending balance	(8,924)	(39,077)	(8,924)	(39,077)
Net Unrealized Gains (Losses) on AFS Securities [Member]
Accumulated other comprehensive income (loss), beginning balance	292	(21,060)	(16,762)	(7,534)
Other comprehensive income (loss) before reclassifications	2,886	(4,531)	19,879	(18,057)
Amounts reclassed from accumulated other comprehensive income (loss)	0	0	61	0
Total other comprehensive income (loss), net of tax	2,886	(4,531)	19,940	(18,057)
Accumulated other comprehensive income (loss), ending balance	3,178	(25,591)	3,178	(25,591)
Net Unrealized Losses on Cash Flow Hedges [Member]
Accumulated other comprehensive income (loss), beginning balance	(873)	826	191	(428)
Other comprehensive income (loss) before reclassifications	(217)	(478)	(1,265)	582
Amounts reclassed from accumulated other comprehensive income (loss)	46	633	30	827
Total other comprehensive income (loss), net of tax	(171)	155	(1,235)	1,409
Accumulated other comprehensive income (loss), ending balance	(1,044)	981	(1,044)	981
Pension Benefit Adjustment [Member]
Accumulated other comprehensive income (loss), beginning balance	(11,285)	(14,828)	(11,738)	(15,548)
Other comprehensive income (loss) before reclassifications	0	0	0	0
Amounts reclassed from accumulated other comprehensive income (loss)	227	361	680	1,081
Total other comprehensive income (loss), net of tax	227	361	680	1,081
Accumulated other comprehensive income (loss), ending balance	$ (11,058)	$ (14,467)	$ (11,058)	$ (14,467)