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Fair Value Measurements and Fair Value of Financial Instruments, Estimated Fair Values of Financial Instruments (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Financial assets [Abstract]
HTM securities	$ 600,176	$ 636,827
Carrying Amount [Member] | Level 1 [Member]
Financial liabilities [Abstract]
Subordinated debt	100,000	100,000
Carrying Amount [Member] | Level 2 [Member]
Financial assets [Abstract]
HTM securities	592,999	616,560
Financial liabilities [Abstract]
Time deposits	604,373	633,479
Long-term debt	14,069	39,097
Junior subordinated debt	101,196	101,196
Carrying Amount [Member] | Level 3 [Member]
Financial assets [Abstract]
Net loans	7,634,754	7,390,004
Estimated Fair Value [Member] | Level 1 [Member]
Financial liabilities [Abstract]
Subordinated debt	105,024	103,277
Estimated Fair Value [Member] | Level 2 [Member]
Financial assets [Abstract]
HTM securities	600,176	636,827
Financial liabilities [Abstract]
Time deposits	606,134	638,721
Long-term debt	14,651	39,820
Junior subordinated debt	108,841	108,926
Estimated Fair Value [Member] | Level 3 [Member]
Financial assets [Abstract]
Net loans	$ 7,677,033	$ 7,530,033

X

- Definition

Fair value of junior subordinated debt obligations including, but not limited to, subordinated loan, subordinated bond, subordinated debenture or junior debt.

+ References

No definition available.

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- Definition

Fair value portion of time deposit liabilities, including certificates of deposit.

+ References

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- Definition

Fair value portion of debt instrument payable, including, but not limited to, notes payable and loans payable.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 50
-Paragraph 10
-URI http://asc.fasb.org/extlink&oid=121572278&loc=d3e13433-108611

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- Definition

Fair value of subordinated debt obligations including, but not limited to, subordinated loan, subordinated bond, subordinated debenture or junior debt.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
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-Paragraph 2
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-URI http://asc.fasb.org/extlink&oid=117815213&loc=d3e19207-110258

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- Definition

Fair value of investment in debt security measured at amortized cost (held-to-maturity).

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 5
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-URI http://asc.fasb.org/extlink&oid=121645371&loc=d3e27232-111563

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03(6))
-URI http://asc.fasb.org/extlink&oid=120398452&loc=d3e534808-122878

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 5A
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=121645371&loc=SL120269820-111563

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- Definition

Fair value portion of loans held-for-sale including, but not limited to, mortgage loans and finance receivables.

+ References

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