Fair Value Measurements (Tables)

3 Months Ended

Mar. 31, 2018

Financial Assets and Financial Liabilities Measured at Fair Value on Recurring Basis

The table below summarizes financial assets and financial liabilities measured at fair value on a recurring basis as of March 31, 2018 and December 31, 2017, segregated by the level of the valuation inputs within the fair value hierarchy of ASC Topic 820 utilized to measure fair value.



	Level 1 Inputs		Level 2 Inputs		Level 3 Inputs		Total Fair Value
March 31, 2018
Securities available for sale:
U.S. Treasury	$	3,418,147	$	—	$	—	$	3,418,147
Residential mortgage-backed securities	—		645,695		—		645,695
States and political subdivisions	—		6,430,105		—		6,430,105
Other	—		42,585		—		42,585
Trading account securities:
U.S. Treasury	19,772		—		—		19,772
Derivative assets:
Interest rate swaps, caps and floors	—		16,812		—		16,812
Commodity swaps and options	—		20,844		1,719		22,563
Foreign currency forward contracts	313		—		—		313
Derivative liabilities:
Interest rate swaps, caps and floors	—		22,658		—		22,658
Commodity swaps and options	—		22,356		—		22,356
Foreign currency forward contracts	208		—		—		208
December 31, 2017
Securities available for sale:
U.S. Treasury	$	3,445,153	$	—	$	—	$	3,445,153
Residential mortgage-backed securities	—		665,086		—		665,086
States and political subdivisions	—		6,336,209		—		6,336,209
Other	—		42,561		—		42,561
Trading account securities:
U.S. Treasury	19,210		—		—		19,210
States and political subdivisions	—		1,888		—		1,888
Derivative assets:
Interest rate swaps, caps and floors	—		20,022		—		20,022
Commodity swaps and options	—		14,408		1,233		15,641
Foreign currency forward contracts	415		—		—		415
Derivative liabilities:
Interest rate swaps, caps and floors	—		18,754		—		18,754
Commodity swaps and options	—		15,327		—		15,327
Foreign currency forward contracts	239		—		—		239

Impaired Loans Remeasured And Reported At Fair Value Specific Valuation Allowance Allocation Method Of Underlying Collateral [Table Text Block]

The following table presents impaired loans that were remeasured and reported at fair value through a specific valuation allowance allocation of the allowance for loan losses based upon the fair value of the underlying collateral during the reported periods.



	Three Months Ended March 31, 2018						Three Months Ended March 31, 2017
	Level 2			Level 3			Level 2		Level 3
Carrying value of impaired loans before allocations	$	365		$	56,788		$	—	$	24,171
Specific valuation allowance (allocations) reversals of prior allocations	(64		)	(1,520		)	—		(1,340		)
Fair value	$	301		$	55,268		$	—	$	22,831

Foreclosed Assets Remeasured and Reported at Fair Value

The following table presents foreclosed assets that were remeasured and reported at fair value during the reported periods:



	Three Months Ended March 31, 2018
	2018			2017
Foreclosed assets remeasured at initial recognition:
Carrying value of foreclosed assets prior to remeasurement	$	7		$	—
Charge-offs recognized in the allowance for loan losses	—			—
Fair value	$	7		$	—
Foreclosed assets remeasured subsequent to initial recognition:
Carrying value of foreclosed assets prior to remeasurement	$	1,823		$	89
Write-downs included in other non-interest expense	(473		)	(16		)
Fair value	$	1,350		$	73

Estimated Fair Values of Financial Instruments

The estimated fair values of financial instruments that are reported at amortized cost in our consolidated balance sheets, segregated by the level of the valuation inputs within the fair value hierarchy utilized to measure fair value, were as follows:



	March 31, 2018				December 31, 2017
	Carrying Amount		Estimated Fair Value		Carrying Amount		Estimated Fair Value
Financial assets:
Level 2 inputs:
Cash and cash equivalents	$	4,680,948	$	4,680,948	$	5,053,047	$	5,053,047
Securities held to maturity	1,247,154		1,257,886		1,432,098		1,455,791
Cash surrender value of life insurance policies	181,297		181,297		180,477		180,477
Accrued interest receivable	125,485		125,485		167,508		167,508
Level 3 inputs:
Loans, net	13,214,144		13,184,663		12,990,301		12,981,165
Financial liabilities:
Level 2 inputs:
Deposits	26,677,778		26,671,005		26,872,389		26,866,676
Federal funds purchased and repurchase agreements	1,032,221		1,032,221		1,147,824		1,147,824
Junior subordinated deferrable interest debentures	136,198		137,115		136,184		137,115
Subordinated notes payable and other borrowings	98,591		103,409		98,552		105,311
Accrued interest payable	3,196		3,196		3,358		3,358