Schedule of recorded amount of assets and liabilities measured at fair value on a recurring basis


			Quoted Prices
			In Active		Significant
			Markets		Other		Significant
			for Identical		Observable		Unobservable
			Assets		Inputs		Inputs
(Dollars in thousands)	Fair Value		(Level 1)		(Level 2)		(Level 3)
March 31, 2022:
Assets
Derivative financial instruments	$	412,815	$	—	$	412,815	$	—
Loans held for sale		130,376		—		130,376		—
Trading securities		74,234		—		74,234		—
Securities available for sale:
U.S. Treasuries		268,581		—		268,581		—
U.S. Government agencies		179,942		—		179,942		—
Residential mortgage-backed securities issued by U.S. government
agencies or sponsored enterprises		2,013,904		—		2,013,904		—
Residential collateralized mortgage-obligations issued by U.S. government
agencies or sponsored enterprises		694,705		—		694,705		—
Commercial mortgage-backed securities issued by U.S. government
agencies or sponsored enterprises		1,151,860		—		1,151,860		—
State and municipal obligations		1,127,697		—		1,127,697		—
Small Business Administration loan-backed securities		457,357		—		457,357		—
Corporate securities		30,160		—		30,160		—
Total securities available for sale		5,924,206		—		5,924,206		—
Mortgage servicing rights		83,339		—		—		83,339
	$	6,624,970	$	—	$	6,541,631	$	83,339
Liabilities
Derivative financial instruments	$	412,168	$	—	$	412,168	$	—

December 31, 2021:
Assets
Derivative financial instruments	$	414,742	$	—	$	414,742	$	—
Loans held for sale		191,723		—		191,723		—
Trading securities		77,689		—		77,689		—
Securities available for sale:
U.S. Government agencies		97,117		—		97,117		—
Residential mortgage-backed securities issued by U.S. government
agencies or sponsored enterprises		1,831,039		—		1,831,039		—
Residential collateralized mortgage-obligations issued by U.S. government
agencies or sponsored enterprises		725,995		—		725,995		—
Commercial mortgage-backed securities issued by U.S. government
agencies or sponsored enterprises		1,207,241		—		1,207,241		—
State and municipal obligations		812,689		—		812,689		—
Small Business Administration loan-backed securities		500,663		—		500,663		—
Corporate securities		18,734		—		18,734		—
Total securities available for sale		5,193,478		—		5,193,478		—
Mortgage servicing rights		65,620		—		—		65,620
	$	5,943,252	$	—	$	5,877,632	$	65,620
Liabilities
Derivative financial instruments	$	410,137	$	—	$	410,137	$	—

Schedule of amounts of assets and liabilities measured at fair value on a nonrecurring basis


			Quoted Prices
			In Active		Significant
			Markets		Other		Significant
			for Identical		Observable		Unobservable
			Assets		Inputs		Inputs
(Dollars in thousands)	Fair Value		(Level 1)		(Level 2)		(Level 3)
March 31, 2022:
OREO	$	3,290	$	—	$	—	$	3,290
Bank property held for sale		6,417		—		—		6,417
Individually evaluated loans		4,527		—		—		4,527
December 31, 2021:
OREO	$	2,736	$	—	$	—	$	2,736
Bank property held for sale		9,578		—		—		9,578
Individually evaluated loans		20,802		—		—		20,802

Schedule of estimated fair value, and related carrying amount, of the Company's financial instruments


	Carrying		Fair
(Dollars in thousands)	Amount		Value		Level 1		Level 2		Level 3
March 31, 2022
Financial assets:
Cash and cash equivalents	$	6,032,606	$	6,032,606	$	6,032,606	$	—	$	—
Trading securities		74,234		74,234		—		74,234		—
Investment securities		8,931,233		8,733,959		179,258		8,554,701		—
Loans held for sale		130,376		130,376		—		130,376		—
Loans, net of allowance for credit losses		26,256,031		26,434,330		—		—		26,434,330
Accrued interest receivable		106,396		106,396		—		25,425		80,971
Mortgage servicing rights		83,339		83,339		—		—		83,339
Interest rate swap - non-designated hedge		408,434		408,434		—		408,434		—
Other derivative financial instruments (mortgage banking related)		4,381		4,381		—		4,381		—
Financial liabilities:
Deposits		38,775,830		38,737,371		—		38,737,371		—
Federal funds purchased and securities sold under agreements to repurchase		770,409		770,409		—		770,409		—
Other borrowings		405,553		399,125		—		399,125		—
Accrued interest payable		6,644		6,644		—		6,644		—
Interest rate swap - non-designated hedge		409,084		409,084		—		409,084		—
Other derivative financial instruments (mortgage banking related)		3,084		3,084		—		3,084		—
Off balance sheet financial instruments:
Commitments to extend credit		—		63,247		—		63,247		—
December 31, 2021
Financial assets:
Cash and cash equivalents	$	6,843,147	$	6,843,147	$	6,843,147	$	—	$	—
Trading securities		77,689		77,689		—		77,689		—
Investment securities		7,173,947		7,132,110		160,568		6,971,542		—
Loans held for sale		191,723		191,723		—		191,723		—
Loans, net of allowance for credit losses		23,626,359		23,921,372		—		—		23,921,372
Accrued interest receivable		90,069		90,069		—		19,241		70,828
Mortgage servicing rights		65,620		65,620		—		—		65,620
Interest rate swap - non-designated hedge		408,776		408,776		—		408,776		—
Other derivative financial instruments (mortgage banking related)		5,966		5,966		—		5,966		—
Financial liabilities:
Deposits		35,054,829		35,050,516		—		35,050,516		—
Federal funds purchased and securities sold under agreements to repurchase		781,239		781,239		—		781,239		—
Other borrowings		327,066		334,640		—		334,640		—
Accrued interest payable		3,345		3,345		—		3,345		—
Interest rate swap - non-designated hedge		410,137		410,137		—		410,137		—
Off balance sheet financial instruments:
Commitments to extend credit		—		93,501		—		93,501		—