Fair Value of Financial Instruments, Carrying Amount and Estimated Fair Value of Financial Instruments (Details) - USD ($) $ in Thousands		Dec. 31, 2019	Dec. 31, 2018
Financial assets [Abstract]
Securities held-to-maturity, fair value		$ 201,217	$ 193,131
Quoted Market Prices in an Active Market (Level 1)
Financial assets [Abstract]
Securities held-to-maturity, fair value		0	0
Loans Receivable, Fair Value Disclosure		0	0
Consumer loans held-for-sale		0	0
Commercial loans held-for-sale		0	0
Financial liabilities [Abstract]
Deposits and securities sold under agreements to repurchase, fair value disclosure		0	0
Federal Home Loan Bank advances		0	0
Subordinated debt and other borrowings		0	0
Off-balance sheet instruments [Abstract]
Commitments to extend credit	[1]	0	0
Standby letters of credit	[2]	0	0
Models with Significant Observable Market Parameters (Level 2)
Financial assets [Abstract]
Securities held-to-maturity, fair value		201,217	193,131
Loans Receivable, Fair Value Disclosure		0	0
Consumer loans held-for-sale		82,986	34,929
Commercial loans held-for-sale		17,836	16,296
Financial liabilities [Abstract]
Deposits and securities sold under agreements to repurchase, fair value disclosure		0	0
Federal Home Loan Bank advances		0	0
Subordinated debt and other borrowings		0	0
Off-balance sheet instruments [Abstract]
Commitments to extend credit	[1]	0	0
Standby letters of credit	[2]	0	0
Models with Significant Unobservable Market Parameters (Level 3)
Financial assets [Abstract]
Securities held-to-maturity, fair value		0	0
Loans Receivable, Fair Value Disclosure		19,717,845	17,288,795
Consumer loans held-for-sale		0	0
Commercial loans held-for-sale		0	0
Financial liabilities [Abstract]
Deposits and securities sold under agreements to repurchase, fair value disclosure		19,647,392	18,337,848
Federal Home Loan Bank advances		2,078,514	1,432,003
Subordinated debt and other borrowings		712,220	464,616
Off-balance sheet instruments [Abstract]
Commitments to extend credit	[1]	2,364	1,733
Standby letters of credit	[2]	1,422	1,131
Reported Value Measurement [Member]
Financial assets [Abstract]
Securities held-to-maturity, fair value		188,996	194,282
Loans Receivable, Fair Value Disclosure		19,693,099	17,623,974
Consumer loans held-for-sale		81,820	34,196
Commercial loans held-for-sale		17,585	15,954
Financial liabilities [Abstract]
Deposits and securities sold under agreements to repurchase, fair value disclosure		20,307,382	18,953,848
Federal Home Loan Bank advances		2,062,534	1,443,589
Subordinated debt and other borrowings		749,080	485,130
Off-balance sheet instruments [Abstract]
Commitments to extend credit	[1]	7,938,341	6,921,689
Standby letters of credit	[2]	203,579	177,475
Estimate of Fair Value Measurement [Member]
Financial assets [Abstract]
Securities held-to-maturity, fair value	[3]	201,217	193,131
Loans Receivable, Fair Value Disclosure	[3]	19,717,845	17,288,795
Consumer loans held-for-sale	[3]	82,986	34,929
Commercial loans held-for-sale	[3]	17,836	16,296
Financial liabilities [Abstract]
Deposits and securities sold under agreements to repurchase, fair value disclosure	[3]	19,647,392	18,337,848
Federal Home Loan Bank advances	[3]	2,078,514	1,432,003
Subordinated debt and other borrowings	[3]	712,220	464,616
Off-balance sheet instruments [Abstract]
Commitments to extend credit	[1],[3]	2,364	1,733
Standby letters of credit	[2],[3]	$ 1,422	$ 1,131

[1] At the end of each period, Pinnacle Financial evaluates the inherent risks of the outstanding off-balance sheet commitments. In making this evaluation, Pinnacle Financial evaluates the credit worthiness of the borrower, the collateral supporting the commitments and any other factors similar to those used to evaluate the inherent risks of our loan portfolio. Additionally, Pinnacle Financial evaluates the probability that the outstanding commitment will eventually become a funded loan. As a result, at December 31, 2019 and 2018, respectively, Pinnacle Financial included in other liabilities $2.4 million and $1.7 million representing the inherent risks associated with these off-balance sheet commitments.

[2] At December 31, 2019 and 2018, the fair value of Pinnacle Financial's standby letters of credit totaled $1.4 million and $1.1 million, respectively. This amount represents the unamortized fee associated with these standby letters of credit, which were priced at market when issued, and is included in the consolidated balance sheet of Pinnacle Financial and is believed to approximate fair value.  This fair value will decrease over time as the existing standby letters of credit approach their expiration dates.

[3] Estimated fair values are consistent with an exit-price concept. The assumptions used to estimate the fair values are intended to approximate those that a market-participant would realize in a hypothetical orderly transaction.