Regulatory Matters (Details) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2018 USD ($) $ / shares
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Preceding period of retained earnings used in calculation of dividend payable	2 years
Quarterly common stock dividend (in dollar per share) | $ / shares	$ 0.14
Pinnacle Financial
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Cash dividends paid to Pinnacle Financial by Pinnacle Bank	$ 25,100
Actual
Total capital to risk weighted assets	2,325,113
Tier I capital to risk weighted assets	1,781,355
Common Equity Tier I capital to risk weighted assets	1,781,233
Tier I capital to average assets	$ 1,781,355	[1]
Actual
Total capital to risk weighted assets (as percent)	12.10%
Tier I capital to risk weighted assets (as percent)	9.20%
Common Equity Tier I capital to risk weighted assets (as percent)	9.20%
Tier I capital to average assets (as percent)	8.80%	[1]
Minimum Capital Requirement
Total capital to risk weighted assets	$ 1,542,891
Tier I capital to risk weighted assets	1,157,168
Common Equity Tier I capital	867,876
Tier I capital to average assets	$ 809,553	[1]
Minimum Capital Requirement
Total capital to risk weighted assets (as percent)	8.00%
Tier I capital to risk weighted assets (as percent)	6.00%
Common Equity Tier I capital to risk weighted assets (as percent)	4.50%
Tier I capital to average assets (as percent)	4.00%	[1]
Pinnacle Bank
Actual
Total capital to risk weighted assets	$ 2,180,680
Tier I capital to risk weighted assets	1,979,624
Common Equity Tier I capital to risk weighted assets	1,979,502
Tier I capital to average assets	$ 1,979,624	[1]
Actual
Total capital to risk weighted assets (as percent)	11.30%
Tier I capital to risk weighted assets (as percent)	10.30%
Common Equity Tier I capital to risk weighted assets (as percent)	10.30%
Tier I capital to average assets (as percent)	9.80%	[1]
Minimum Capital Requirement
Total capital to risk weighted assets	$ 1,538,121
Tier I capital to risk weighted assets	1,153,591
Common Equity Tier I capital	865,193
Tier I capital to average assets	$ 807,086	[1]
Minimum Capital Requirement
Total capital to risk weighted assets (as percent)	8.00%
Tier I capital to risk weighted assets (as percent)	6.00%
Common Equity Tier I capital to risk weighted assets (as percent)	4.50%
Tier I capital to average assets (as percent)	4.00%	[1]
Minimum To Be Well-Capitalized
Total capital to risk weighted assets	$ 1,922,651
Tier I capital to risk weighted assets	1,538,121
Common Equity Tier I capital to risk weighted assets	1,249,723
Tier I capital to average assets	$ 1,008,857	[1]
Minimum To Be Well-Capitalized
Total capital to risk weighted assets (as percent)	10.00%
Tier I capital to risk weighted assets (as percent)	8.00%
Common Equity Tier I capital to risk weighted assets (as percent)	6.50%
Tier I capital to average assets (as percent)	5.00%	[1]

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