Securities - Amortized Cost and Fair Value of Securities Available for Sale (Details) - USD ($) $ in Thousands	Sep. 30, 2022	Dec. 31, 2021
Amortized cost and fair value of securities available for sale
Amortized Cost	$ 1,780,914	$ 2,400,956
Gross Unrealized Gains	104	16,120
Gross Unrealized Losses	(211,776)	(31,024)
Fair Value	1,569,242	2,386,052
Obligations of other U.S. Government agencies and corporations
Amortized cost and fair value of securities available for sale
Amortized Cost	170,000
Gross Unrealized Gains	0
Gross Unrealized Losses	(5,480)
Fair Value	164,520
U.S. Treasury securities
Amortized cost and fair value of securities available for sale
Amortized Cost		3,007
Gross Unrealized Gains		3
Gross Unrealized Losses		0
Fair Value		3,010
Obligations of states and political subdivisions
Amortized cost and fair value of securities available for sale
Amortized Cost	155,188	153,847
Gross Unrealized Gains	88	5,532
Gross Unrealized Losses	(14,635)	(269)
Fair Value	140,641	159,110
Other debt securities
Amortized cost and fair value of securities available for sale
Amortized Cost	74,888	36,515
Gross Unrealized Gains	3	1,097
Gross Unrealized Losses	(3,571)	(148)
Fair Value	71,320	37,464
Government agency mortgage backed securities \| Residential mortgage backed securities:
Amortized cost and fair value of securities available for sale
Amortized Cost	528,196	967,497
Gross Unrealized Gains	13	7,854
Gross Unrealized Losses	(59,181)	(6,816)
Fair Value	469,028	968,535
Government agency mortgage backed securities \| Commercial mortgage backed securities:
Amortized cost and fair value of securities available for sale
Amortized Cost	11,204	14,717
Gross Unrealized Gains	0	365
Gross Unrealized Losses	(957)	(1)
Fair Value	10,247	15,081
Government agency collateralized mortgage obligations \| Residential mortgage backed securities:
Amortized cost and fair value of securities available for sale
Amortized Cost	626,821	1,008,514
Gross Unrealized Gains	0	457
Gross Unrealized Losses	(102,823)	(20,371)
Fair Value	523,998	988,600
Government agency collateralized mortgage obligations \| Commercial mortgage backed securities:
Amortized cost and fair value of securities available for sale
Amortized Cost	214,617	216,859
Gross Unrealized Gains	0	812
Gross Unrealized Losses	(25,129)	(3,419)
Fair Value	$ 189,488	$ 214,252

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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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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