Allowance for Loan Losses - Loan Portfolio and Related Allowance (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Recorded Investment
Individually Evaluated for Impairment	$ 36,096	$ 36,700
Collectively Evaluated for Impairment	32,296	29,695
Total	5,185,738	4,810,780
Associated Allowance
Individually Evaluated for Impairment	2,858	2,728
Collectively Evaluated for Impairment	5,149,642	4,774,080
Total	35,154	32,423
Real Estate \| Construction and land development
Recorded Investment
Individually Evaluated for Impairment	5,057	211
Collectively Evaluated for Impairment	1,828	2,211
Total	324,953	443,417
Associated Allowance
Individually Evaluated for Impairment	14	22
Collectively Evaluated for Impairment	319,896	443,206
Total	1,842	2,233
Real Estate \| Commercial real estate
Recorded Investment
Individually Evaluated for Impairment	10,267	13,638
Collectively Evaluated for Impairment	13,004	10,743
Total	2,368,754	2,121,238
Associated Allowance
Individually Evaluated for Impairment	220	369
Collectively Evaluated for Impairment	2,358,487	2,107,600
Total	13,224	11,112
Real Estate \| Residential real estate
Recorded Investment
Individually Evaluated for Impairment	14,383	19,047
Collectively Evaluated for Impairment	6,833	6,970
Total	1,506,153	1,321,659
Associated Allowance
Individually Evaluated for Impairment	834	805
Collectively Evaluated for Impairment	1,491,770	1,302,612
Total	7,667	7,775
Commercial and financial \| Commercial and financial
Recorded Investment
Individually Evaluated for Impairment	6,052	3,322
Collectively Evaluated for Impairment	7,985	7,087
Total	777,673	721,585
Associated Allowance
Individually Evaluated for Impairment	1,731	1,498
Collectively Evaluated for Impairment	771,621	718,263
Total	9,716	8,585
Consumer \| Consumer
Recorded Investment
Individually Evaluated for Impairment	337	482
Collectively Evaluated for Impairment	2,646	2,684
Total	208,205	202,881
Associated Allowance
Individually Evaluated for Impairment	59	34
Collectively Evaluated for Impairment	207,868	202,399
Total	2,705	2,718
PCI Loans
Recorded Investment
Individually Evaluated for Impairment	12,666	14,434
Associated Allowance
Individually Evaluated for Impairment	0	0
PCI Loans \| Real Estate \| Construction and land development
Recorded Investment
Individually Evaluated for Impairment	160	151
Associated Allowance
Individually Evaluated for Impairment	0	0
PCI Loans \| Real Estate \| Commercial real estate
Recorded Investment
Individually Evaluated for Impairment	10,217	10,828
Associated Allowance
Individually Evaluated for Impairment	0	0
PCI Loans \| Real Estate \| Residential real estate
Recorded Investment
Individually Evaluated for Impairment	1,710	2,718
Associated Allowance
Individually Evaluated for Impairment	0	0
PCI Loans \| Commercial and financial \| Commercial and financial
Recorded Investment
Individually Evaluated for Impairment	579	737
Associated Allowance
Individually Evaluated for Impairment	0	0
PCI Loans \| Consumer \| Consumer
Recorded Investment
Individually Evaluated for Impairment	0	0
Associated Allowance
Individually Evaluated for Impairment	$ 0	$ 0

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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 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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