Securities - Amortized cost and fair value of the Corporations investments (Details) - USD ($) $ in Thousands	Sep. 30, 2022	Dec. 31, 2021
Amortized cost and fair value of investments classified as available for sale
Amortized Cost	$ 1,527,938	$ 1,344,790
Unrealized Gains	3,299	30,126
Unrealized Losses	(199,252)	(10,182)
Fair Value	1,331,985	1,364,734
U.S. Government agencies
Amortized cost and fair value of investments classified as available for sale
Amortized Cost	117,925	118,176
Unrealized Gains	26	2,688
Unrealized Losses	(11,670)	(741)
Fair Value	106,281	120,123
Mortgage Backed Securities - residential
Amortized cost and fair value of investments classified as available for sale
Amortized Cost	725,085	628,920
Unrealized Gains	22	4,387
Unrealized Losses	(106,138)	(6,879)
Fair Value	618,969	626,428
Mortgage Backed Securities - commercial
Amortized cost and fair value of investments classified as available for sale
Amortized Cost	11,763	15,480
Unrealized Gains		191
Unrealized Losses	(454)
Fair Value	11,309	15,671
Collateralized Mortgage Obligations
Amortized cost and fair value of investments classified as available for sale
Amortized Cost	230,237	175,501
Unrealized Gains		1,272
Unrealized Losses	(23,877)	(1,768)
Fair Value	206,360	175,005
State and municipal obligations
Amortized cost and fair value of investments classified as available for sale
Amortized Cost	399,040	362,843
Unrealized Gains	100	17,833
Unrealized Losses	(50,325)	(578)
Fair Value	348,815	380,098
Municipal taxable
Amortized cost and fair value of investments classified as available for sale
Amortized Cost	39,326	38,445
Unrealized Gains	40	396
Unrealized Losses	(6,760)	(215)
Fair Value	32,606	38,626
U.S. Treasury
Amortized cost and fair value of investments classified as available for sale
Amortized Cost	2,084	205
Unrealized Losses	(28)	(1)
Fair Value	2,056	204
Collateralized debt obligations
Amortized cost and fair value of investments classified as available for sale
Unrealized Gains	3,111	3,359
Fair Value	3,111	3,359
Other securities
Amortized cost and fair value of investments classified as available for sale
Amortized Cost	2,478	5,220
Fair Value	$ 2,478	$ 5,220

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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Amortized cost of 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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