Securities (Schedule of Securities Available-for-Sale) (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	$ 828,810	$ 821,254
Gross Unrealized Gains	22,821	5,436
Gross Unrealized Losses	(2,186)	(14,079)
Fair Value	849,445	812,611
Obligations of State and Political Subdivisions
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	300,448	291,449
Gross Unrealized Gains	17,028	4,407
Gross Unrealized Losses	(4)	(1,323)
Fair Value	317,472	294,533
MBS/CMO - Residential
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	528,362	529,805
Gross Unrealized Gains	5,793	1,029
Gross Unrealized Losses	(2,182)	(12,756)
Fair Value	$ 531,973	$ 518,078

Amount, before tax, of unrealized gain in accumulated other comprehensive income (AOCI) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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Amount, before tax, of unrealized loss in accumulated other comprehensive income (AOCI) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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