Fair Value Measurements (Tables)

9 Months Ended

Sep. 30, 2018

Fair Value Disclosures [Abstract]

Assets and Liabilities Measured at Fair Value on Recurring Basis

Assets measured at fair value on a recurring basis as of September 30, 2018 and December 31, 2017(in thousands):

	Fair Value Measurement at September 30, 2018
Description	September 30, 2018		Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
Assets
U.S. Treasury	$	35	$	35	$	—	$	—
U.S. Agencies		9,171		—		9,171		—
State and political subdivisions		49,406		—		49,406		—
Corporates		9,488		9,488		—		—
Trading – other		13,059		12,547		512		—
Trading securities		81,159		22,070		59,089		—
U.S. Treasury		37,938		37,938		—		—
U.S. Agencies		198		—		198		—
Mortgage-backed		3,620,378		—		3,620,378		—
State and political subdivisions		2,274,227		—		2,274,227		—
Corporates		—		—		—		—
Available for sale securities		5,932,741		37,938		5,894,803		—
Company-owned life insurance		58,314		—		58,314		—
Bank-owned life insurance		271,623		—		271,623		—
Derivatives		2,499		—		2,499		—
Total	$	6,346,336	$	60,008	$	6,286,328	$	—
Liabilities
Deferred compensation	$	55,012	$	55,012	$	—	$	—
Derivatives		11,465		—		11,465		—
Securities sold not yet purchased		40,342		—		40,342		—
Total	$	106,819	$	55,012	$	51,807	$	—

	Fair Value Measurement at December 31, 2017
Description	December 31, 2017		Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
Assets
U.S. Treasury	$	18	$	18	$	—	$	—
U.S. Agencies		9,976		—		9,976		—
Mortgage-backed		1,949		—		1,949		—
State and political subdivisions		27,114		—		27,114		—
Corporates		1,885		1,885		—		—
Trading – other		13,113		12,434		679		—
Trading securities		54,055		14,337		39,718		—
U.S. Treasury		38,643		38,643		—		—
U.S. Agencies		14,752		—		14,752		—
Mortgage-backed		3,649,243		—		3,649,243		—
State and political subdivisions		2,542,673		—		2,542,673		—
Corporates		13,266		13,266		—		—
Available for sale securities		6,258,577		51,909		6,206,668		—
Company-owned life insurance		53,577		—		53,577		—
Bank-owned life insurance		265,823		—		265,823		—
Derivatives		10,149		—		10,149		—
Total	$	6,642,181	$	66,246	$	6,575,935	$	—
Liabilities
Deferred compensation	$	50,963	$	50,963	$	—	$	—
Derivatives		8,906		—		8,906		—
Securities sold not yet purchased		4,130		—		4,130		—
Total	$	63,999	$	50,963	$	13,036	$	—

Assets Measured at Fair Value on Non-Recurring Basis

Assets measured at fair value on a non-recurring basis as of September 30, 2018 and December 31, 2017(in thousands):

	Fair Value Measurement at September 30, 2018 Using
Description	September 30, 2018		Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)		Total Gains Recognized During the Nine Months Ended September 30
Impaired loans	$	10,614	$	—	$	—	$	10,614	$	2,073
Other real estate owned		3,619		—		—		3,619		—
Total	$	14,233	$	—	$	—	$	14,233	$	2,073

	Fair Value Measurement at December 31, 2017 Using
Description	December 31, 2017		Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)		Total Gains Recognized During the Twelve Months Ended December 31
Impaired loans	$	15,186	$	—	$	—	$	15,186	$	1,251
Other real estate owned		1,488		—		—		1,488		13
Total	$	16,674	$	—	$	—	$	16,674	$	1,264

Estimated Fair Value of Financial Instruments

The estimated fair value of the Company’s financial instruments at September 30, 2018 and December 31, 2017 are as follows (in thousands):

	Fair Value Measurement at September 30, 2018 Using
	Carrying Amount		Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)		Total Estimated Fair Value
FINANCIAL ASSETS
Cash and short-term investments	$	1,224,102	$	1,024,423	$	199,679	$	—	$	1,224,102
Securities available for sale		5,932,741		37,938		5,894,803		—		5,932,741
Securities held to maturity		1,199,114		—		1,091,640		—		1,091,640
Trading securities		81,159		22,070		59,089		—		81,159
Other securities		65,252		—		65,252		—		65,252
Loans (exclusive of allowance for loan loss)		11,966,946		—		11,938,756		—		11,938,756
Derivatives		2,499		—		2,499		—		2,499
FINANCIAL LIABILITIES
Demand and savings deposits		16,696,192		16,696,192		—		—		16,696,192
Time deposits		1,040,512		—		1,040,512		—		1,040,512
Other borrowings		1,192,985		—		1,192,985		—		1,192,985
Long-term debt		78,523		—		78,775		—		78,775
Derivatives		11,465		—		11,465		—		11,465
OFF-BALANCE SHEET ARRANGEMENTS
Commitments to extend credit for loans										3,970
Commercial letters of credit										79
Standby letters of credit										1,935

	Fair Value Measurement at December 31, 2017 Using
	Carrying Amount		Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)		Total Estimated Fair Value
FINANCIAL ASSETS
Cash and short-term investments	$	1,936,084	$	1,749,618	$	186,466	$	—	$	1,936,084
Securities available for sale		6,258,577		51,909		6,206,668		—		6,258,577
Securities held to maturity		1,261,014		—		1,207,447		—		1,207,447
Trading securities		54,055		14,337		39,718		—		54,055
Other securities		65,897		—		65,897		—		65,897
Loans (exclusive of allowance for loan loss)		11,281,973		—		11,318,764		—		11,318,764
Derivatives		10,149		—		10,149		—		10,149
FINANCIAL LIABILITIES
Demand and savings deposits		16,742,736		16,742,736		—		—		16,742,736
Time deposits		1,280,264		—		1,280,264		—		1,280,264
Other borrowings		1,260,704		11,334		1,249,370		—		1,260,704
Long-term debt		79,281		—		79,496		—		79,496
Derivatives		8,906		—		8,906		—		8,906
OFF-BALANCE SHEET ARRANGEMENTS
Commitments to extend credit for loans										6,654
Commercial letters of credit										136
Standby letters of credit										2,514