Fair Value (Tables)

9 Months Ended

Sep. 30, 2021

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 September 30, 2021 and December 31, 2020, 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 nine months ended September 30, 2021 and the year ended December 31, 2020.

	September 30, 2021
	Total		Level 1		Level 2		Level 3
U.S. Treasury securities	$	278,615	$	278,615	$	—	$	—
U.S. Government agency obligations		14,979		—		14,979		—
Obligations of states and political subdivisions		5,734		—		5,734		—
Mortgage-backed securities		2,758,277		—		2,758,277		—
Securities available for sale		3,057,605		278,615		2,778,990		—
Loans held for sale		335,339		—		335,339		—
Mortgage servicing rights		84,101		—		—		84,101
Other assets - derivatives		26,341		25		23,807		2,509
Other liabilities - derivatives		7,443		4,768		2,675		—

	December 31, 2020
	Total		Level 1		Level 2		Level 3
U.S. Government agency obligations	$	18,041	$	—	$	18,041	$	—
Obligations of states and political subdivisions		5,835		—		5,835		—
Mortgage-backed securities		1,967,939		—		1,967,939		—
Securities available for sale		1,991,815		—		1,991,815		—
Loans held for sale		446,951		—		446,951		—
Mortgage servicing rights		66,464		—		—		66,464
Other assets - derivatives		47,768		145		38,063		9,560
Other liabilities - derivatives		5,324		666		4,658		—

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 nine months ended September 30, 2021 and 2020 are summarized as follows ($ in thousands):

	MSR			Other Assets - Derivatives
Balance, January 1, 2021	$	66,464		$	9,560
Total net (loss) gain included in Mortgage banking, net (1)		(4,378	)		7,664
Additions		22,015			—
Sales		—			(14,715	)
Balance, September 30, 2021	$	84,101		$	2,509
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 September 30, 2021	$	11,037		$	2,722
Balance, January 1, 2020	$	79,394		$	1,439
Total net (loss) gain included in Mortgage banking, net (1)		(38,509	)		32,833
Additions		20,728			—
Sales		—			(22,059	)
Balance, September 30, 2020	$	61,613		$	12,213
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 September 30, 2020	$	(27,098	)	$	19,930

(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 September 30, 2021 and December 31, 2020, are as follows ($ in thousands):

	September 30, 2021				December 31, 2020
	Carrying Value		Estimated Fair Value		Carrying Value		Estimated Fair Value
Financial Assets:
Level 2 Inputs:
Cash and short-term investments	$	2,175,058	$	2,175,058	$	1,952,554	$	1,952,554
Securities held to maturity		394,905		411,132		538,072		563,115
Level 3 Inputs:
Net LHFI and PPP loans		10,117,312		10,072,186		10,317,352		10,312,395
Financial Liabilities:
Level 2 Inputs:
Deposits		14,922,839		14,923,369		14,048,764		14,052,863
Federal funds purchased and securities sold under    repurchase agreements		146,417		146,417		164,519		164,519
Other borrowings		94,889		94,888		168,252		168,252
Subordinated notes		122,987		129,375		122,921		127,500
Junior subordinated debt securities		61,856		48,866		61,856		46,083

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 September 30, 2021 and December 31, 2020 ($ in thousands):

	September 30, 2021		December 31, 2020
Fair value of LHFS	$	247,377	$	305,791
LHFS contractual principal outstanding		241,023		290,625
Fair value less unpaid principal	$	6,354	$	15,166