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Accumulated Other Comprehensive Income (Loss) (Components of unrealized holding gains on AFS securities) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Accumulated Other Comprehensive Income (Loss) [Line Items]
Unrealized gains (losses) on AFS securities arising during the period	$ 2,059	$ 4,876	$ 8,370	$ 10,830
Reclassification adjustment for net (gains) losses included in net income	0	0	(71)	0
Tax effect	(379)	(1,018)	(1,772)	(2,213)
Unrealized gains (losses), net of tax	1,657	3,757	6,396	8,452
Unrealized Holding Gains (Losses) on AFS Securities [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Unrealized gains (losses) on AFS securities arising during the period	2,059	4,876	8,370	10,830
Reclassification adjustment for net (gains) losses included in net income			(71)	0
Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment, before Tax, Portion Attributable to Parent			8,299	10,830
Tax effect	(379)	(1,018)	(1,772)	(2,213)
Unrealized gains (losses), net of tax	1,680	3,858	6,527	8,617
Unrealized Holding Gains (Losses) on AFS Securities [Member] | Auction Rate Money Market Preferred and Preferred Stocks [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Unrealized gains (losses) on AFS securities arising during the period	253	30	(140)	295
Reclassification adjustment for net (gains) losses included in net income			0	0
Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment, before Tax, Portion Attributable to Parent			(140)	295
Tax effect	0	0	0	0
Unrealized gains (losses), net of tax	253	30	(140)	295
Unrealized Holding Gains (Losses) on AFS Securities [Member] | All Other AFS Securities [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Unrealized gains (losses) on AFS securities arising during the period	1,806	4,846	8,510	10,535
Reclassification adjustment for net (gains) losses included in net income			(71)	0
Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment, before Tax, Portion Attributable to Parent			8,439	10,535
Tax effect	(379)	(1,018)	(1,772)	(2,213)
Unrealized gains (losses), net of tax	1,427	3,828	6,667	8,322
Accumulated Defined Benefit Plans Adjustment [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Unrealized gains (losses), net of tax	$ 0	$ 0	$ 0	$ 0

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Amount before tax, after reclassification adjustments, of appreciation (loss) in value of unsold available-for-sale securities, attributable to parent entity. Excludes amounts related to other than temporary impairment (OTTI) loss.

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Amount of tax expense (benefit), after reclassification adjustments, of appreciation (loss) in value of unsold available-for-sale securities. Excludes amounts related to other than temporary impairment (OTTI) loss.

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