Fair Value (Tables)

3 Months Ended

Mar. 31, 2019

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 as of March 31, 2019 and December 31, 2018, 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, 2019 and the year ended December 31, 2018.

	March 31, 2019
	Total		Level 1		Level 2		Level 3
U.S. Government agency obligations	$	28,008	$	—	$	28,008	$	—
Obligations of states and political subdivisions		50,954		—		50,954		—
Mortgage-backed securities		1,644,483		—		1,644,483		—
Securities available for sale		1,723,445		—		1,723,445		—
Loans held for sale		172,683		—		172,683		—
Mortgage servicing rights		86,842		—		—		86,842
Other assets - derivatives		13,820		3,702		8,353		1,765
Other liabilities - derivatives		3,418		262		3,156		—

	December 31, 2018
	Total		Level 1		Level 2		Level 3
U.S. Government agency obligations	$	30,335	$	—	$	30,335	$	—
Obligations of states and political subdivisions		50,676		—		50,676		—
Mortgage-backed securities		1,730,802		—		1,730,802		—
Securities available for sale		1,811,813		—		1,811,813		—
Loans held for sale		153,799		—		153,799		—
Mortgage servicing rights		95,596		—		—		95,596
Other assets - derivatives		12,347		5,006		6,154		1,187
Other liabilities - derivatives		4,213		66		4,147		—

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, 2019 and 2018 are summarized as follows ($ in thousands):

	MSR			Other Assets - Derivatives
Balance, January 1, 2019	$	95,596		$	1,187
Total net (loss) gain included in Mortgage banking, net (1)		(11,261	)		1,574
Additions		2,507			—
Sales		—			(996	)
Balance, March 31, 2019	$	86,842		$	1,765
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, 2019	$	(8,863	)	$	382
Balance, January 1, 2018	$	84,269		$	900
Total net (loss) gain included in Mortgage banking, net (1)		7,014			1,533
Additions		3,567			—
Sales		—			(760	)
Balance, March 31, 2018	$	94,850		$	1,673
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, 2018	$	9,521		$	239

(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, 2019 and December 31, 2018, are as follows ($ in thousands):

	March 31, 2019				December 31, 2018
	Carrying Value		Estimated Fair Value		Carrying Value		Estimated Fair Value
Financial Assets:
Level 2 Inputs:
Cash and short-term investments	$	454,047	$	454,047	$	350,391	$	350,391
Securities held to maturity		884,319		874,858		909,643		889,733
Level 3 Inputs:
Net LHFI		8,916,009		8,934,375		8,756,578		8,757,817
Net acquired loans		91,904		91,904		105,701		105,701
Financial Liabilities:
Level 2 Inputs:
Deposits		11,534,815		11,535,520		11,364,411		11,365,203
Federal funds purchased and securities sold under    repurchase agreements		46,867		46,867		50,471		50,471
Other borrowings		83,265		83,223		79,885		79,827
Junior subordinated debt securities		61,856		51,959		61,856		53,196

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 the LHFS accounted for under the fair value option as of March 31, 2019 and December 31, 2018 ($ in thousands):

	March 31, 2019		December 31, 2018
Fair value of LHFS	$	118,853	$	92,235
LHFS contractual principal outstanding		114,950		89,056
Fair value less unpaid principal	$	3,903	$	3,179