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Premises and Equipment - Additional Information (Detail) - USD ($) $ in Thousands | 12 Months Ended
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Dec. 31, 2020 | Dec. 31, 2019 | Dec. 31, 2018
Property, Plant and Equipment [Line Items] |  |  |
Operating Lease, Right-of-Use Asset | $ 42,617 | $ 48,642 |
Operating Lease, Liability | 46,819 | 52,894 |
Premises and equipment, available-for-sale | 2,600 |  |
Operating Leases, Rent Expense, Contingent Rentals | 6,700 | 4,900 | $ 4,100
Gain (Loss) on Termination of Lease | 700 |  |
Assets |  |  |
Property, Plant and Equipment [Line Items] |  |  |
Gain (Loss) on Contract Termination | 3,800 |  |
Liability |  |  |
Property, Plant and Equipment [Line Items] |  |  |
Gain (Loss) on Contract Termination | 3,600 |  |
Premises and Equipment [Member] |  |  |
Property, Plant and Equipment [Line Items] |  |  |
Depreciation included in noninterest expense | 10,900 | 10,500 | $ 9,500
Property Subject to Operating Lease [Member] |  |  |
Property, Plant and Equipment [Line Items] |  |  |
Depreciation included in noninterest expense | 2,600 | $ 3,500 |
Accounting Standards Update 2016-02 [Member] |  |  |
Property, Plant and Equipment [Line Items] |  |  |
Operating Lease, Right-of-Use Asset | 38,500 |  |
Operating Lease, Liability | $ 41,800 |  |

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- Definition The amount of expense recognized in the current period that reflects the allocation of the cost of tangible assets over the assets' useful lives. Includes production and non-production related depreciation. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 360 -SubTopic 10 -Section 50 -Paragraph 1 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=6391035&loc=d3e2868-110229 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 28 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=118932676&loc=d3e3602-108585 + Details
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- Definition Gain (loss) related to the termination of a contract between the parties. The termination may be due to many causes including early termination of a lease by a lessee, a breach of contract by one party, or a failure to perform. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 28 -URI http://asc.fasb.org/extlink&oid=118932676&loc=d3e3602-108585 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 420 -SubTopic 10 -Section 50 -Paragraph 1 -Subparagraph (b)(1) -URI http://asc.fasb.org/extlink&oid=6394359&loc=d3e17939-110869 + Details
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- Definition Amount of gain (loss) on termination of lease before expiration of lease term. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 842 -SubTopic 20 -Section 40 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=77888415&loc=SL77918607-209975 + Details
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- Definition Amount of rent expense incurred for leased assets, including but not limited to, furniture and equipment, that is not directly or indirectly associated with the manufacture, sale or creation of a product or product line. + References No definition available. + Details
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- Definition Present value of lessee's discounted obligation for lease payments from operating lease. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 842 -SubTopic 20 -Section 45 -Paragraph 1 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=77888419&loc=SL77918627-209977 + Details
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- Definition Amount of lessee's right to use underlying asset under operating lease. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 842 -SubTopic 20 -Section 45 -Paragraph 1 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=77888419&loc=SL77918627-209977 + Details
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