Regulatory Matters (Details) - USD ($) $ / shares in Units, $ in Thousands		12 Months Ended
		Dec. 31, 2019	Dec. 31, 2018	Mar. 31, 2016	Mar. 31, 2015	Dec. 31, 2013
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Preceding period of retained earnings used in calculation of dividend payable		2 years
Retained earnings		$ 1,184,183	$ 833,130
SEC Schedule, 12-04, Cash Dividends Paid to Registrant, Consolidated Subsidiaries		114,000
Dividends Payable, Amount Per Share			$ 0.16	$ 0.14	$ 0.12	$ 0.08
Pinnacle Bank
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Retained earnings		721,200
Actual Amount
Total capital to risk weighted assets:		2,906,853	$ 2,432,419
Tier I capital to risk weighted assets:		2,679,713	2,218,003
Common Equity Tier I Capital to risk weighted assets		2,679,590	2,217,880
Tier I capital to average assets (*):	[1]	$ 2,679,713	$ 2,218,003
Actual Ratios
Total capital to risk weighted assets:		12.20%	11.50%
Tier I capital to risk weighted assets:		11.20%	10.50%
Common Equity Tier I Capital to Risk Weighted Assets		11.20%	10.50%
Tier I capital to average assets (*):	[1]	10.50%	9.80%
Minimum Capital Requirement
Total capital to risk weighted assets:		$ 1,906,839	$ 1,686,046
Tier I capital to risk weighted assets:		1,430,129	1,264,535
Common Equity Tier I Risk Based Capital to risk weighted assets		1,072,597	948,401
Tier I capital to average assets (*):	[1]	$ 1,019,210	$ 906,185
Minimum Capital Requirement - Ratios
Total capital to risk weighted assets:		8.00%	8.00%
Tier I capital to risk weighted assets:		6.00%	6.00%
Common Equity Tier I Risk Based Capital to risk weighted assets:		4.50%	4.50%
Tier I capital to average assets (*):	[1]	4.00%	4.00%
Minimum To Be Well Capitalized
Total capital to risk weighted assets:		$ 2,383,549	$ 2,107,558
Tier I capital to risk weighted assets:		1,906,839	1,686,046
Common Equity Tier I capital to risk weighted assets		1,549,307	1,369,912
Tier I capital to average assets (*):	[1]	$ 1,274,012	$ 1,132,731
Minimum To Be Well Capitalized - Ratios
Total capital to risk weighted assets:		10.00%	10.00%
Tier I capital to risk weighted assets:		8.00%	8.00%
Common Equity Tier I capital to risk weighted assets:		6.50%	6.50%
Tier I capital to average assets (*):	[1]	5.00%	5.00%
Pinnacle Financial
Actual Amount
Total capital to risk weighted assets:		$ 3,159,375	$ 2,580,143
Tier I capital to risk weighted assets:		2,319,234	2,024,193
Common Equity Tier I Capital to risk weighted assets		2,319,112	2,024,070
Tier I capital to average assets (*):	[1]	$ 2,319,234	$ 2,024,193
Actual Ratios
Total capital to risk weighted assets:		13.20%	12.20%
Tier I capital to risk weighted assets:		9.70%	9.60%
Common Equity Tier I Capital to Risk Weighted Assets		9.70%	9.60%
Tier I capital to average assets (*):	[1]	9.10%	8.90%
Minimum Capital Requirement
Total capital to risk weighted assets:		$ 1,912,885	$ 1,691,017
Tier I capital to risk weighted assets:		1,434,664	1,268,263
Common Equity Tier I Risk Based Capital to risk weighted assets		1,075,998	951,197
Tier I capital to average assets (*):	[1]	$ 1,021,836	$ 909,102
Minimum Capital Requirement - Ratios
Total capital to risk weighted assets:		8.00%	8.00%
Tier I capital to risk weighted assets:		6.00%	6.00%
Common Equity Tier I Risk Based Capital to risk weighted assets:		4.50%	4.50%
Tier I capital to average assets (*):	[1]	4.00%	4.00%
Minimum To Be Well Capitalized
Total capital to risk weighted assets:		$ 2,391,106	$ 2,113,772
Tier I capital to risk weighted assets:		$ 1,912,885	$ 1,691,017
Minimum To Be Well Capitalized - Ratios
Total capital to risk weighted assets:		10.00%	10.00%
Tier I capital to risk weighted assets:		8.00%	8.00%

[1] (*) Average assets for the above calculations were based on the most recent quarter.