Regulatory Matters (Details) - USD ($)		3 Months Ended
		Mar. 31, 2019	Dec. 31, 2018
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		$ 914,545,000	$ 833,130,000
Quarterly common stock dividend (in dollar per share)		$ 0.16
Pinnacle Financial
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Cash dividends paid to Pinnacle Financial by Pinnacle Bank		$ 39,100,000
Actual
Total capital to risk weighted assets		2,635,562,000	2,580,143,000
Tier I capital to risk weighted assets		2,078,454,000	2,024,193,000
Common Equity Tier I capital to risk weighted assets		2,078,331,000	2,024,070,000
Tier I capital to average assets	[1]	$ 2,078,454,000	$ 2,024,193,000
Actual
Total capital to risk weighted assets (as percent)		12.00%	12.20%
Tier I capital to risk weighted assets (as percent)		9.40%	9.60%
Common Equity Tier I capital to risk weighted assets (as percent)		9.40%	9.60%
Tier I capital to average assets (as percent)	[1]	9.00%	8.90%
Minimum Capital Requirement
Total capital to risk weighted assets		$ 1,760,157,000	$ 1,691,017,000
Tier I capital to risk weighted assets		1,320,118,000	1,268,263,000
Common Equity Tier I capital		990,088,000	951,197,000
Tier I capital to average assets	[1]	$ 924,540,000	$ 909,102,000
Minimum Capital Requirement
Total capital to risk weighted assets (as percent)		8.00%	8.00%
Tier I capital to risk weighted assets (as percent)		6.00%	6.00%
Common Equity Tier I capital to risk weighted assets (as percent)		4.50%	4.50%
Tier I capital to average assets (as percent)	[1]	4.00%	4.00%
Pinnacle Bank
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Retained earnings		$ 637,400,000
Actual
Total capital to risk weighted assets		2,495,127,000	$ 2,432,419,000
Tier I capital to risk weighted assets		2,277,027,000	2,218,003,000
Common Equity Tier I capital to risk weighted assets		2,276,904,000	2,217,880,000
Tier I capital to average assets	[1]	$ 2,277,027,000	$ 2,218,003,000
Actual
Total capital to risk weighted assets (as percent)		11.40%	11.50%
Tier I capital to risk weighted assets (as percent)		10.40%	10.50%
Common Equity Tier I capital to risk weighted assets (as percent)		10.40%	10.50%
Tier I capital to average assets (as percent)	[1]	9.90%	9.80%
Minimum Capital Requirement
Total capital to risk weighted assets		$ 1,756,333,000	$ 1,686,046,000
Tier I capital to risk weighted assets		1,317,250,000	1,264,535,000
Common Equity Tier I capital		987,937,000	948,401,000
Tier I capital to average assets	[1]	$ 922,810,000	$ 906,185,000
Minimum Capital Requirement
Total capital to risk weighted assets (as percent)		8.00%	8.00%
Tier I capital to risk weighted assets (as percent)		6.00%	6.00%
Common Equity Tier I capital to risk weighted assets (as percent)		4.50%	4.50%
Tier I capital to average assets (as percent)	[1]	4.00%	4.00%
Minimum To Be Well-Capitalized
Total capital to risk weighted assets		$ 2,195,416,000	$ 2,107,558,000
Tier I capital to risk weighted assets		1,756,333,000	1,686,046,000
Common Equity Tier I capital to risk weighted assets		1,427,020,000	1,369,912,000
Tier I capital to average assets	[1]	$ 1,153,512,000	$ 1,132,731,000
Minimum To Be Well-Capitalized
Total capital to risk weighted assets (as percent)		10.00%	10.00%
Tier I capital to risk weighted assets (as percent)		8.00%	8.00%
Common Equity Tier I capital to risk weighted assets (as percent)		6.50%	6.50%
Tier I capital to average assets (as percent)	[1]	5.00%	5.00%

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