Regulatory Matters (Details) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	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	$ 519,144,543	$ 381,072,505
Cash Dividends Paid to Parent Company by Consolidated Subsidiaries	63,100,000
Dividends Payable, Amount Per Share			$ 0.14	$ 0.12	$ 0.08
Pinnacle Bank [Member]
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Retained earnings	305,100,000
Actual Amount
Total capital to risk weighted assets:	2,134,344,000	1,136,782,000
Tier I capital to risk weighted assets:	1,936,313,000	949,193,000
Common Equity Tier I Capital to risk weighted assets	1,936,209,000	949,070,000
Tier I capital to average assets (*):	$ 1,936,313,000	$ 949,193,000
Actual Ratios
Total capital to risk weighted assets:	11.3471%	11.20%
Tier I capital to risk weighted assets:	10.2943%	9.30%
Common Equity Tier I Capital to Risk Weighted Assets	10.2938%	9.30%
Tier I capital to average assets (*):	9.70%	9.20%
Minimum Capital Requirement
Total capital to risk weighted assets:	$ 1,504,765,000	$ 814,254,000
Tier I capital to risk weighted assets:	1,128,574,000	610,690,000
Common Equity Tier I Risk Based Capital to risk weighted assets	846,430,000	458,018,000
Tier I capital to average assets (*):	$ 796,235,000	$ 412,124,000
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 (*):	4.00%	4.00%
Minimum To Be Well Capitalized
Total capital to risk weighted assets:	$ 1,880,956,000	$ 1,017,817,000
Tier I capital to risk weighted assets:	1,504,765,000	814,254,000
Common Equity Tier I capital to risk weighted assets	1,222,621,000	661,581,000
Tier I capital to average assets (*):	$ 995,294,000	$ 515,155,000
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 (*):	5.00%	5.00%
Pinnacle Financial [Member]
Actual Amount
Total capital to risk weighted assets:	$ 2,266,161,000	$ 1,211,105,000
Tier I capital to risk weighted assets:	1,725,323,000	882,654,000
Common Equity Tier I Capital to risk weighted assets	1,725,219,000	802,532,000
Tier I capital to average assets (*):	$ 1,725,323,000	$ 882,654,000
Actual Ratios
Total capital to risk weighted assets:	12.0102%	11.90%
Tier I capital to risk weighted assets:	9.1438%	8.60%
Common Equity Tier I Capital to Risk Weighted Assets	9.1433%	7.90%
Tier I capital to average assets (*):	8.60%	8.60%
Minimum Capital Requirement
Total capital to risk weighted assets:	$ 1,509,496,000	$ 816,857,000
Tier I capital to risk weighted assets:	1,132,122,000	612,643,000
Common Equity Tier I Risk Based Capital to risk weighted assets	849,092,000	459,482,000
Tier I capital to average assets (*):	$ 797,861,000	$ 412,902,000
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 (*):	4.00%	4.00%