Securities (Tables)

12 Months Ended

Dec. 31, 2018

Investments, Debt and Equity Securities [Abstract]

Summary of Amortized Cost and Fair Value of Available-for-sale and Held-to-maturity Securities

The amortized cost and fair value of securities available-for-sale and held-to-maturity at December 31, 2018 and 2017 are summarized as follows (in thousands):

	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Fair Value
December 31, 2018
Securities available-for-sale:
U.S Treasury securities	$	30,325	$	—	$	25	$	30,300
U.S. Government agency securities	71,456		49		1,346		70,159
Mortgage-backed securities	1,336,469		3,110		28,634		1,310,945
State and municipal securities	1,244,471		3,785		18,602		1,229,654
Asset-backed securities	379,107		820		4,345		375,582
Corporate notes	69,399		170		2,523		67,046
	$	3,131,227	$	7,934	$	55,475	$	3,083,686
Securities held-to-maturity:
State and municipal securities	194,282		152		1,303		193,131
	$	194,282	$	152	$	1,303	$	193,131
December 31, 2017
Securities available-for-sale:
U.S Treasury securities	$	30,505	$	—	$	60	$	30,445
U.S. Government agency securities	182,500		67		1,766		180,801
Mortgage-backed securities	1,270,625		5,318		12,124		1,263,819
State and municipal securities	774,949		12,251		2,588		784,612
Asset-backed securities	173,346		262		316		173,292
Corporate notes	81,615		1,346		647		82,314
	$	2,513,540	$	19,244	$	17,501	$	2,515,283
Securities held-to-maturity:
State and municipal securities	20,762		114		46		20,830
	$	20,762	$	114	$	46	$	20,830

In 2018, Pinnacle Financial transferred, at fair value, $179.8 million of municipal securities from the available-for-sale portfolio to the held-to-maturity portfolio. The related net unrealized after tax losses of $2.2 million remained in accumulated other comprehensive income (loss) and will be amortized over the remaining life of the securities, offsetting the related amortization of discount on the transferred securities. No gains or losses were recognized at the time of the transfer. At December 31, 2018, approximately $1.2 billion of Pinnacle Financial's investment portfolio was pledged to secure public funds and other deposits and securities sold under agreements to repurchase. At December 31, 2018, repurchase agreements comprised of secured borrowings totaled $104.7 million and were secured by $104.7 million of pledged U.S. government agency securities, municipal securities, asset backed securities, and corporate debentures. As the fair value of securities pledged to secure repurchase agreements may decline, Pinnacle Financial regularly evaluates its need to pledge additional securities for the counterparty to remain adequately secured.

Amortized Cost and Fair Value of Debt Securities by Contractual Maturity

The amortized cost and fair value of debt securities as of December 31, 2018 by contractual maturity are shown below. Actual maturities may differ from contractual maturities of mortgage-backed securities since the mortgages underlying the securities may be called or prepaid with or without penalty. Therefore, these securities are not included in the maturity categories in the following summary (in thousands):

	Available-for-sale				Held-to-maturity
	Amortized Cost		Fair Value		Amortized Cost		Fair Value
Due in one year or less	$	47,546	$	47,474	$	325	$	326
Due in one year to five years	45,037		44,925		5,710		5,700
Due in five years to ten years	100,401		98,424		7,980		7,935
Due after ten years	1,222,667		1,206,336		180,267		179,170
Mortgage-backed securities	1,336,469		1,310,945		—		—
Asset-backed securities	379,107		375,582		—		—
	$	3,131,227	$	3,083,686	$	194,282	$	193,131

Classification of Investments According to Term of Unrealized Losses of Less than Twelve Months or Twelve Months or Longer

At December 31, 2018 and 2017, included in securities were the following investments with unrealized losses. The information below classifies these investments according to the term of the unrealized loss of less than twelve months or twelve months or longer (in thousands):

	Investments with an Unrealized Loss of less than 12 months				Investments with an Unrealized Loss of 12 months or longer				Total Investments with an Unrealized Loss
	Fair Value		Unrealized Losses		Fair Value		Unrealized Losses		Fair Value		Unrealized Losses
December 31, 2018
U.S. Treasury securities	$	30,054	$	22	$	246	$	3	$	30,300	$	25
U.S. government agency securities	13,697		328		42,539		1,018		56,236		1,346
Mortgage-backed securities	203,299		2,134		882,231		26,500		1,085,530		28,634
State and municipal securities	805,821		18,643		198,610		4,078		1,004,431		22,721
Asset-backed securities	268,677		4,118		11,828		227		280,505		4,345
Corporate notes	26,272		1,538		25,915		985		52,187		2,523
Total temporarily-impaired securities	$	1,347,820	$	26,783	$	1,161,369	$	32,811	$	2,509,189	$	59,594
December 31, 2017
U.S. Treasury securities	$	29,948	$	60	$	—	$	—	$	29,948	$	60
U.S. government agency securities	173,677		1,766		—		—		173,677		1,766
Mortgage-backed securities	607,408		5,042		285,561		7,082		892,969		12,124
State and municipal securities	115,403		1,408		50,083		1,226		165,486		2,634
Asset-backed securities	68,742		198		14,136		118		82,878		316
Corporate notes	22,168		547		11,944		100		34,112		647
Total temporarily-impaired securities	$	1,017,346	$	9,021	$	361,724	$	8,526	$	1,379,070	$	17,547