Loans and Allowance for Loan Losses Loans and Allowance for Loan Losses - Details on Allowance for Loan Losses and Recorded Investment by Loan Classification (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning Balance	$ 94,777	$ 83,575	$ 67,240
Charged-off loans	(49,333)	(28,467)	(30,400)
Recovery of previously charged-off loans	9,962	12,386	12,358
Provision for credit losses	191,542	27,283	34,377
Ending Balance	285,050	94,777	83,575
Collectively Evaluated for Impairment		90,512
Individually Evaluated for Impairment		3,280
Ending Balance	285,050	94,777	83,575
Collectively Evaluated for Impairment		19,708,817
Individually Evaluated for Impairment	74,292	58,144
Loans acquired with deteriorated credit quality		20,915
Loans	22,424,501	19,787,876
Currently performing impaired loans	51,700	35,800
Financing Receivable, Allowance for Credit Loss, Period Increase (Decrease)	38,102
Nonaccrual loans	73,836	61,605
Financial Asset Acquired with Credit Deterioration
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Individually Evaluated for Impairment		0
Commercial Real Estate
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning Balance	33,369
Ending Balance		33,369
Collectively Evaluated for Impairment		32,134
Individually Evaluated for Impairment		1,235
Ending Balance		33,369
Collectively Evaluated for Impairment		7,681,608
Individually Evaluated for Impairment		18,122
Loans acquired with deteriorated credit quality		9,488
Loans		7,709,218
Commercial Real Estate \| Financial Asset Acquired with Credit Deterioration
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Individually Evaluated for Impairment		0
Commercial Real Estate Owner Occupied
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning Balance	13,406	10,575	8,992
Charged-off loans	(2,598)	(1,625)	(2,652)
Recovery of previously charged-off loans	1,317	1,252	1,568
Provision for credit losses	10,909	3,204	2,667
Ending Balance	23,298	13,406	10,575
Ending Balance	23,298	13,406	10,575
Individually Evaluated for Impairment	15,681
Loans	2,802,227	2,669,766
Financing Receivable, Allowance for Credit Loss, Period Increase (Decrease)	264
Nonaccrual loans	10,231	11,654
Commercial real estate non owner occupied
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning Balance	19,963	16,371	12,196
Charged-off loans	(546)	(75)	(378)
Recovery of previously charged-off loans	911	980	528
Provision for credit losses	63,544	2,687	4,025
Ending Balance	79,132	19,963	16,371
Ending Balance	79,132	19,963	16,371
Individually Evaluated for Impairment	7,000
Loans	5,203,384	5,039,452
Financing Receivable, Allowance for Credit Loss, Period Increase (Decrease)	(4,740)
Nonaccrual loans	5,219	7,173
Consumer Real Estate
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning Balance	8,054	7,670	5,031
Charged-off loans	(3,478)	(1,335)	(1,593)
Recovery of previously charged-off loans	1,493	1,827	2,653
Provision for credit losses	6,206	(108)	1,579
Ending Balance	33,304	8,054	7,670
Collectively Evaluated for Impairment		6,762
Individually Evaluated for Impairment		1,292
Ending Balance	33,304	8,054	7,670
Collectively Evaluated for Impairment		3,036,922
Individually Evaluated for Impairment	27,082	25,018
Loans acquired with deteriorated credit quality		6,685
Loans	3,099,172	3,068,625
Financing Receivable, Allowance for Credit Loss, Period Increase (Decrease)	21,029
Consumer Real Estate \| Financial Asset Acquired with Credit Deterioration
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Individually Evaluated for Impairment		0
Construction and Land Development
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning Balance	12,662	11,128	8,962
Charged-off loans	0	(18)	(74)
Recovery of previously charged-off loans	147	682	1,863
Provision for credit losses	32,743	870	377
Ending Balance	42,408	12,662	11,128
Collectively Evaluated for Impairment		12,629
Individually Evaluated for Impairment		33
Ending Balance	42,408	12,662	11,128
Collectively Evaluated for Impairment		2,426,901
Individually Evaluated for Impairment	2,049	561
Loans acquired with deteriorated credit quality		3,021
Loans	2,901,746	2,430,483
Financing Receivable, Allowance for Credit Loss, Period Increase (Decrease)	(3,144)
Nonaccrual loans	1,953	2,278
Construction and Land Development \| Financial Asset Acquired with Credit Deterioration
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Individually Evaluated for Impairment		0
Commercial and Industrial
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning Balance	36,112	31,731	24,863
Charged-off loans	(38,718)	(19,208)	(13,175)
Recovery of previously charged-off loans	4,540	6,473	3,035
Provision for credit losses	73,449	17,116	17,008
Ending Balance	98,423	36,112	31,731
Collectively Evaluated for Impairment		35,401
Individually Evaluated for Impairment		711
Ending Balance	98,423	36,112	31,731
Collectively Evaluated for Impairment		6,274,280
Individually Evaluated for Impairment	22,476	14,295
Loans acquired with deteriorated credit quality		1,721
Loans	8,038,457	6,290,296
Financing Receivable, Allowance for Credit Loss, Period Increase (Decrease)	23,040
Commercial and Industrial \| Financial Asset Acquired with Credit Deterioration
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Individually Evaluated for Impairment		0
Consumer and Other
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning Balance	3,595	5,423	5,874
Charged-off loans	(3,993)	(6,206)	(12,528)
Recovery of previously charged-off loans	1,554	1,172	2,711
Provision for credit losses	4,691	3,206	9,366
Ending Balance	8,485	3,595	5,423
Collectively Evaluated for Impairment		3,586
Individually Evaluated for Impairment		9
Ending Balance	8,485	3,595	5,423
Collectively Evaluated for Impairment		289,106
Individually Evaluated for Impairment	4	148
Loans acquired with deteriorated credit quality		0
Loans	379,515	289,254
Financing Receivable, Allowance for Credit Loss, Period Increase (Decrease)	2,638
Nonaccrual loans	4	148
Consumer and Other \| Financial Asset Acquired with Credit Deterioration
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Individually Evaluated for Impairment		0
Unallocated Financing Receivables
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning Balance	985	677	1,322
Charged-off loans	0	0	0
Recovery of previously charged-off loans	0	0	0
Provision for credit losses	0	308	(645)
Ending Balance	0	985	677
Ending Balance	0	$ 985	$ 677
Financing Receivable, Allowance for Credit Loss, Period Increase (Decrease)	$ (985)

Refers to financing receivable impaired loans that are current and in performing status.

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Amount of allowance for credit loss on financing receivable. Excludes allowance for financing receivable covered under loss sharing agreement.

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The valuation allowance for financing receivables that are expected to be uncollectible that were collectively evaluated for impairment.

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Amount of valuation allowance for financing receivables that are expected to be uncollectible that were individually evaluated for impairment.

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Amount of increase (decrease) in allowance for credit loss on financing receivable.

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Amount of increase in allowance for credit loss on financing receivable from recovery.

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A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

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Amount of writeoff of financing receivable, charged against allowance for credit loss.

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The balance of financing receivables that were collectively evaluated for impairment.

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The balance of financing receivables that were individually evaluated for impairment.

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Reflects the carrying amount of loans deemed to be questionable as to collection on which no interest is continuing to be recognized.

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Amount before allowance and after deduction of deferred interest and fees, unamortized costs and premiums and discounts from face amounts, of loans and leases held in portfolio, including but not limited to, commercial and consumer loans. Excludes loans and leases covered under loss sharing agreements.

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Amount, after allowance for credit loss, of financing receivable. Excludes financing receivable covered under loss sharing agreement.

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Amount of expense related to estimated loss from loan and lease transactions.

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