Parent Company Only Financial Information (Details) - USD ($)	3 Months Ended												12 Months Ended
	Dec. 31, 2023	Sep. 30, 2023	Jun. 30, 2023	Mar. 31, 2023	Dec. 31, 2022	Sep. 30, 2022	Jun. 30, 2022	Mar. 31, 2022	Dec. 31, 2021	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Investment in unconsolidated subsidiaries:
Other assets	$ 2,613,139,000				$ 2,015,441,000								$ 2,613,139,000	$ 2,015,441,000
Total assets	47,959,883,000				41,970,021,000								47,959,883,000	41,970,021,000
Liabilities and Equity [Abstract]
Subordinated debt and other borrowings	424,938,000				424,055,000								424,938,000	424,055,000
Other Liabilities	544,722,000				386,512,000								544,722,000	386,512,000
Stockholders' equity	6,035,788,000				5,519,392,000				$ 5,310,607,000				6,035,788,000	5,519,392,000	$ 5,310,607,000	$ 4,904,611,000
Total liabilities and shareholders' equity	47,959,883,000				41,970,021,000								47,959,883,000	41,970,021,000
Expenses:
Interest expense													1,091,250,000	244,642,000	98,813,000
Personnel expense, including stock compensation													531,828,000	510,175,000	436,006,000
Income tax expense (benefit)													151,854,000	136,751,000	124,582,000
Net income	94,979,000	$ 132,603,000	$ 197,299,000	$ 137,271,000	137,847,000	$ 148,658,000	$ 145,127,000	$ 129,110,000	133,528,000	$ 136,577,000	$ 131,790,000	$ 125,428,000	562,152,000	560,742,000	527,323,000
Preferred stock dividends													15,192,000	15,192,000	15,192,000
Net income available to common shareholders	91,181,000	128,805,000	193,501,000	133,473,000	134,049,000	144,860,000	141,329,000	125,312,000	129,730,000	132,779,000	127,992,000	121,630,000	546,960,000	545,550,000	512,131,000
CONDENSED STATEMENTS OF CASH FLOWS [Abstract]
Net income	94,979,000	$ 132,603,000	$ 197,299,000	137,271,000	137,847,000	$ 148,658,000	$ 145,127,000	129,110,000	133,528,000	$ 136,577,000	$ 131,790,000	125,428,000	562,152,000	560,742,000	527,323,000
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation, amortization and accretion													78,698,000	62,298,000	53,256,000
Stock-based compensation expense													41,879,000	39,552,000	24,952,000
Deferred tax (expense) benefit													72,368,000	19,740,000	(12,232,000)
Income from equity method investment													(85,402,000)	(145,466,000)	(122,274,000)
Dividends received from equity method investment													36,694,000	63,114,000	69,996,000
Excess tax benefit from stock compensation													208,000	3,027,000	2,475,000
(Increase) decrease in other assets													(262,851,000)	(82,436,000)	73,542,000
Increase (decrease) in other liabilities													7,944,000	(26,620,000)	(60,315,000)
Net cash provided by operating activities													478,404,000	604,925,000	657,444,000
Investing activities:
Increase in other investments													(92,997,000)	(90,967,000)	(83,830,000)
Net cash used in investing activities													(4,602,439,000)	(6,684,439,000)	(3,612,955,000)
Financing activities:
Issuance of common stock pursuant to restricted stock unit agreement, net of shares withheld for taxes													(3,725,000)	(5,462,000)	(3,790,000)
Common dividends paid													68,737,000	68,194,000	55,504,000
Preferred stock dividends paid													15,192,000	15,192,000	15,192,000
Net cash provided by financing activities													5,177,002,000	3,155,357,000	3,095,601,000
Investment Income, Dividend													106,200,000	110,800,000	99,800,000
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Period Increase (Decrease), Including Exchange Rate Effect													1,052,967,000	(2,924,157,000)	140,090,000
Contribution of Property													134,700,000
Parent Company
Assets [Abstract]
Cash and cash equivalents	197,079,000				186,572,000				184,654,000				197,079,000	186,572,000	184,654,000	$ 275,888,000
Investment in unconsolidated subsidiaries:
Unconsolidated subsidiaries	3,995,000				3,995,000								3,995,000	3,995,000
Other investments	67,848,000				56,957,000								67,848,000	56,957,000
Current income tax receivable	32,466,000				33,870,000								32,466,000	33,870,000
Other assets	144,597,000				57,980,000								144,597,000	57,980,000
Total assets	6,586,188,000				5,978,420,000								6,586,188,000	5,978,420,000
Liabilities and Equity [Abstract]
Subordinated debt and other borrowings	424,938,000				424,055,000								424,938,000	424,055,000
Other Liabilities	125,462,000				34,973,000								125,462,000	34,973,000
Stockholders' equity	6,035,788,000				5,519,392,000								6,035,788,000	5,519,392,000
Total liabilities and shareholders' equity	6,586,188,000				5,978,420,000								6,586,188,000	5,978,420,000
CONDENSED STATEMENTS OF OPERATIONS [Abstract]
Income from equity method investment													0	33,817,000	33,169,000
Other income (loss)													12,360,000	6,478,000	14,945,000
Expenses:
Interest expense													23,263,000	18,590,000	22,903,000
Personnel expense, including stock compensation													41,879,000	39,552,000	24,952,000
Other expense													3,180,000	3,025,000	2,697,000
Income before income taxes and equity in undistributed income of subsidiaries													50,991,000	90,107,000	97,417,000
Income tax expense (benefit)													(13,547,000)	(8,444,000)	(3,088,000)
Income before equity in undistributed income of subsidiaries													64,538,000	98,551,000	100,505,000
Equity in undistributed income of bank subsidiaries													496,236,000	461,004,000	424,978,000
Equity in undistributed income (loss) of nonbank subsidiaries													1,378,000	1,187,000	1,840,000
Net income													562,152,000	560,742,000	527,323,000
Preferred stock dividends													15,192,000	15,192,000	15,192,000
Net income available to common shareholders													546,960,000	545,550,000	512,131,000
CONDENSED STATEMENTS OF CASH FLOWS [Abstract]
Net income													562,152,000	560,742,000	527,323,000
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation, amortization and accretion													883,000	882,000	1,886,000
Stock-based compensation expense													41,879,000	39,552,000	24,952,000
Increase (Decrease) in Income Taxes Payable, Net of Income Taxes Receivable													89,597,000	28,281,000	0
Deferred tax (expense) benefit													3,014,000	1,760,000	2,850,000
Income from equity method investment													0	(33,817,000)	(33,169,000)
Dividends received from equity method investment													0	10,365,000	12,214,000
Excess tax benefit from stock compensation													(208,000)	(3,027,000)	(2,475,000)
Gain on other investments, net													(2,088,000)	(2,563,000)	(10,223,000)
(Increase) decrease in other assets													(88,227,000)	(32,609,000)	19,478,000
Increase (decrease) in other liabilities													1,099,000	3,881,000	2,032,000
Equity in undistributed (income) loss of bank subsidiaries													(496,236,000)	(461,004,000)	(424,978,000)
Equity in undistributed (income) loss of nonbank subsidiaries													(1,378,000)	(1,187,000)	(1,840,000)
Net cash provided by operating activities													110,487,000	111,256,000	118,050,000
Investing activities:
Investment in consolidated nonbanking subsidiaries													(10,000,000)	0	0
Proceeds from Divestiture of Interest in Consolidated Subsidiaries													9,691,000	0	0
Increase in other investments													(8,802,000)	(15,776,000)	(11,668,000)
Net cash used in investing activities													(9,111,000)	(15,776,000)	(11,668,000)
Financing activities:
Repayment of other borrowings													0	0	(120,000,000)
Issuance of common stock pursuant to restricted stock unit agreement, net of shares withheld for taxes													(3,725,000)	(5,462,000)	(3,790,000)
Exercise of common stock options, net of shares surrendered for taxes													(3,215,000)	(4,714,000)	(3,130,000)
Common dividends paid													(68,737,000)	(68,194,000)	(55,504,000)
Preferred stock dividends paid													(15,192,000)	(15,192,000)	(15,192,000)
Net cash provided by financing activities													(90,869,000)	(93,562,000)	(197,616,000)
Cash and cash equivalents, beginning of year				$ 186,572,000				$ 184,654,000				$ 275,888,000	186,572,000	184,654,000	275,888,000
Cash and cash equivalents, end of year	197,079,000				186,572,000				$ 184,654,000				197,079,000	186,572,000	184,654,000
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Period Increase (Decrease), Including Exchange Rate Effect													10,507,000	1,918,000	$ (91,234,000)
Banking
Assets [Abstract]
Investments in consolidated subsidiaries	6,126,172,000				5,626,844,000								$ 6,126,172,000	$ 5,626,844,000
Financing activities:
Revenues													Pinnacle Bank	Pinnacle Bank	Pinnacle Bank
Nonbank subsidiaries
Assets [Abstract]
Investments in consolidated subsidiaries	$ 14,031,000				$ 12,202,000								$ 14,031,000	$ 12,202,000
Financing activities:
Revenues													Pinnacle Bank	Pinnacle Bank	Pinnacle Bank