Fair Value (Tables)

3 Months Ended

Mar. 31, 2022

Fair Value Disclosures [Abstract]

Financial Assets and Liabilities Measured at Fair Value Recurring Basis

The following tables summarize financial assets and financial liabilities measured at fair value on a recurring basis at March 31, 2022 and December 31, 2021, segregated by the level of valuation inputs within the fair value hierarchy utilized to measure fair value ($ in thousands). There were no transfers between fair value levels for the three months ended March 31, 2022 and the year ended December 31, 2021.

	March 31, 2022
	Total		Level 1		Level 2		Level 3
U.S. Treasury securities	$	361,822	$	361,822	$	—	$	—
U.S. Government agency obligations		12,623		—		12,623		—
Obligations of states and political subdivisions		5,359		—		5,359		—
Mortgage-backed securities		2,638,442		—		2,638,442		—
Securities available for sale		3,018,246		361,822		2,656,424		—
Loans held for sale		222,538		—		222,538		—
Mortgage servicing rights		111,050		—		—		111,050
Other assets - derivatives		6,602		1,906		5,216		(520	)
Other liabilities - derivatives		21,892		10,537		11,355		—

	December 31, 2021
	Total		Level 1		Level 2		Level 3
U.S. Treasury securities	$	344,640	$	344,640	$	—	$	—
U.S. Government agency obligations		13,727		—		13,727		—
Obligations of states and political subdivisions		5,714		—		5,714		—
Mortgage-backed securities		2,874,796		—		2,874,796		—
Securities available for sale		3,238,877		344,640		2,894,237		—
LHFS		275,706		—		275,706		—
MSR		87,687		—		—		87,687
Other assets - derivatives		24,809		2,794		20,156		1,859
Other liabilities - derivatives		4,677		414		4,263		—

Changes in Level 3 Assets Measured at Fair Value on a Recurring Basis

The changes in Level 3 assets measured at fair value on a recurring basis for the three months ended March 31, 2022 and 2021 are summarized as follows ($ in thousands):

	MSR		Other Assets - Derivatives
Balance, January 1, 2022	$	87,687	$	1,859
Total net (loss) gain included in Mortgage banking, net (1)		18,235		(842	)
Additions		5,128		—
Sales		—		(1,537	)
Balance, March 31, 2022	$	111,050	$	(520	)
The amount of total gains (losses) for the period included in earnings    that are attributable to the change in unrealized gains or    losses still held at March 31, 2022	$	22,020	$	(1,341	)
Balance, January 1, 2021	$	66,464	$	9,560
Total net (loss) gain included in Mortgage banking, net (1)		8,593		2,748
Additions		7,978		—
Sales		—		(8,203	)
Balance, March 31, 2021	$	83,035	$	4,105
The amount of total gains (losses) for the period included in    earnings that are attributable to the change in unrealized    gains or losses still held at March 31, 2021	$	13,696	$	1,579

(1)Total net (loss) gain included in Mortgage banking, net relating to the MSR includes changes in fair value due to market changes and due to run-off.

Carrying Amounts and Estimated Fair Values of Financial Instruments

The carrying amounts and estimated fair values of financial instruments at March 31, 2022 and December 31, 2021, are as follows ($ in thousands):

	March 31, 2022				December 31, 2021
	Carrying Value		Estimated Fair Value		Carrying Value		Estimated Fair Value
Financial Assets:
Level 2 Inputs:
Cash and short-term investments	$	1,917,564	$	1,917,564	$	2,266,829	$	2,266,829
Securities held to maturity		607,598		594,204		342,537		353,511
Level 3 Inputs:
Net LHFI and PPP loans		10,316,974		10,259,188		10,181,708		10,123,379
Financial Liabilities:
Level 2 Inputs:
Deposits		15,113,292		15,100,199		15,087,160		15,084,440
Federal funds purchased and securities sold under    repurchase agreements		170,499		170,499		238,577		238,577
Other borrowings		84,644		84,639		91,025		91,022
Subordinated notes		123,097		121,250		123,042		128,438
Junior subordinated debt securities		61,856		48,866		61,856		49,485

Fair Value and the Contractual Principal Outstanding of the LHFS

The following table provides information about the fair value and the contractual principal outstanding of LHFS accounted for under the fair value option as of March 31, 2022 and December 31, 2021 ($ in thousands):

	March 31, 2022			December 31, 2021
Fair value of LHFS	$	144,086		$	191,242
LHFS contractual principal outstanding		145,103			186,535
Fair value less unpaid principal	$	(1,017	)	$	4,707