XML 74 R57.htm IDEA: XBRL DOCUMENT
v3.20.4

Investment Securities Available for Sale (Amortized Cost And Estimated Fair Value By Contractual Maturity Of Investment Securities Available For Sale) (Details) - USD ($) $ in Thousands | Dec. 31, 2020 | Dec. 31, 2019
--- | --- | ---
Amortized Cost |  |
Amortized Cost, Within One year | $ 24,847 |
Amortized Cost, 1 to 5 Years | 118,760 |
Amortized Cost, 5 to 10 Years | 306,105 |
Amortized Cost, More Than 10 years | 7,352,152 |
Amortized Cost | 7,801,864 | $ 6,647,791
Fair Value |  |
Fair Value, Within One year | 24,870 |
Fair Value, 1 to 5 Years | 122,940 |
Fair Value, 5 to 10 Years | 318,539 |
Fair Value, More Than 10 years | 7,496,089 |
Total Fair Value | 7,962,438 | 6,778,670
U.S. Treasury securities |  |
Amortized Cost |  |
Amortized Cost, Within One year | 20,257 |
Amortized Cost, 1 to 5 Years | 0 |
Amortized Cost, 5 to 10 Years | 0 |
Amortized Cost, More Than 10 years | 0 |
Amortized Cost | 20,257 | 19,855
Fair Value |  |
Fair Value, Within One year | 20,257 |
Fair Value, 1 to 5 Years | 0 |
Fair Value, 5 to 10 Years | 0 |
Fair Value, More Than 10 years | 0 |
Total Fair Value | 20,257 | 19,855
U.S. Government agency securities |  |
Amortized Cost |  |
Amortized Cost, Within One year | 430 |
Amortized Cost, 1 to 5 Years | 2,085 |
Amortized Cost, 5 to 10 Years | 77,123 |
Amortized Cost, More Than 10 years | 0 |
Amortized Cost | 79,638 | 35,499
Fair Value |  |
Fair Value, Within One year | 432 |
Fair Value, 1 to 5 Years | 2,112 |
Fair Value, 5 to 10 Years | 79,776 |
Fair Value, More Than 10 years | 0 |
Total Fair Value | 82,320 | 36,541
Mortgage-backed securities issued by U.S. Government agencies |  |
Amortized Cost |  |
Amortized Cost, Within One year | 0 |
Amortized Cost, 1 to 5 Years | 1,390 |
Amortized Cost, 5 to 10 Years | 232 |
Amortized Cost, More Than 10 years | 1,214,390 |
Amortized Cost | 1,216,012 | 56,328
Fair Value |  |
Fair Value, Within One year | 0 |
Fair Value, 1 to 5 Years | 1,442 |
Fair Value, 5 to 10 Years | 242 |
Fair Value, More Than 10 years | 1,216,333 |
Total Fair Value | 1,218,017 | 56,816
Mortgage-backed securities issued by U.S. Government sponsored enterprises |  |
Amortized Cost |  |
Amortized Cost, Within One year | 0 |
Amortized Cost, 1 to 5 Years | 231 |
Amortized Cost, 5 to 10 Years | 83,163 |
Amortized Cost, More Than 10 years | 4,782,464 |
Amortized Cost | 4,865,858 | 5,079,396
Fair Value |  |
Fair Value, Within One year | 0 |
Fair Value, 1 to 5 Years | 236 |
Fair Value, 5 to 10 Years | 86,192 |
Fair Value, More Than 10 years | 4,913,618 |
Total Fair Value | 5,000,046 | 5,180,815
Collateralized mortgage obligations issued by U.S. Government agencies or sponsored enterprises |  |
Amortized Cost |  |
Amortized Cost, Within One year | 0 |
Amortized Cost, 1 to 5 Years | 0 |
Amortized Cost, 5 to 10 Years | 225 |
Amortized Cost, More Than 10 years | 1,245,419 |
Amortized Cost | 1,245,644 | 629,706
Fair Value |  |
Fair Value, Within One year | 0 |
Fair Value, 1 to 5 Years | 0 |
Fair Value, 5 to 10 Years | 235 |
Fair Value, More Than 10 years | 1,250,142 |
Total Fair Value | 1,250,377 | 636,851
Commercial mortgage-backed securities issued by U.S. Government agencies or sponsored enterprises |  |
Amortized Cost |  |
Amortized Cost, Within One year | 4,160 |
Amortized Cost, 1 to 5 Years | 105,549 |
Amortized Cost, 5 to 10 Years | 136,656 |
Amortized Cost, More Than 10 years | 107,879 |
Amortized Cost | 354,244 | 357,291
Fair Value |  |
Fair Value, Within One year | 4,181 |
Fair Value, 1 to 5 Years | 109,813 |
Fair Value, 5 to 10 Years | 142,952 |
Fair Value, More Than 10 years | 113,975 |
Total Fair Value | 370,921 | 371,592
Corporate debt securities and other debt securities |  |
Amortized Cost |  |
Amortized Cost, Within One year | 0 |
Amortized Cost, 1 to 5 Years | 9,505 |
Amortized Cost, 5 to 10 Years | 8,706 |
Amortized Cost, More Than 10 years | 2,000 |
Amortized Cost | 20,211 | 144,410
Fair Value |  |
Fair Value, Within One year | 0 |
Fair Value, 1 to 5 Years | 9,337 |
Fair Value, 5 to 10 Years | 9,142 |
Fair Value, More Than 10 years | 2,021 |
Total Fair Value | $ 20,500 | $ 146,725

X
- Definition Amortized cost of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale). + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=121645371&loc=d3e27161-111563 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 326 -SubTopic 30 -Section 45 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=121558606&loc=SL82898722-210454 + Details
Name: | us-gaap_AvailableForSaleDebtSecuritiesAmortizedCostBasis
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amortized cost of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), with single maturity date and allocated without single maturity date, maturing in sixth through tenth fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach). + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 3 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=121645371&loc=d3e27198-111563 + Details
Name: | us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAfterFiveThroughTenYearsAmortizedCost
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Fair value of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), with single maturity date and allocated without single maturity date, maturing in sixth through tenth fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach). + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 3 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=121645371&loc=d3e27198-111563 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 320 -Section 50 -Paragraph 3A -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=120252992&loc=SL120269850-112803 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (d) -URI http://asc.fasb.org/extlink&oid=121645371&loc=d3e27161-111563 + Details
Name: | us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAfterFiveThroughTenYearsFairValue
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amortized cost of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), with single maturity date and allocated without single maturity date, maturing in second through fifth fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach). + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 3 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=121645371&loc=d3e27198-111563 + Details
Name: | us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAfterOneThroughFiveYearsAmortizedCost
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Fair value of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), with single maturity date and allocated without single maturity date, maturing in second through fifth fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach). + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (d) -URI http://asc.fasb.org/extlink&oid=121645371&loc=d3e27161-111563 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 3 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=121645371&loc=d3e27198-111563 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 320 -Section 50 -Paragraph 3A -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=120252992&loc=SL120269850-112803 + Details
Name: | us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAfterOneThroughFiveYearsFairValue
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amortized cost of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), with single maturity date and allocated without single maturity date, maturing after tenth fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach). + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 3 -Subparagraph (d) -URI http://asc.fasb.org/extlink&oid=121645371&loc=d3e27198-111563 + Details
Name: | us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAfterTenYearsAmortizedCost
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Fair value of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), with single maturity date and allocated without single maturity date, maturing after tenth fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach). + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 320 -Section 50 -Paragraph 3A -Subparagraph (d) -URI http://asc.fasb.org/extlink&oid=120252992&loc=SL120269850-112803 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (d) -URI http://asc.fasb.org/extlink&oid=121645371&loc=d3e27161-111563 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 3 -Subparagraph (d) -URI http://asc.fasb.org/extlink&oid=121645371&loc=d3e27198-111563 + Details
Name: | us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAfterTenYearsFairValue
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- References No definition available. + Details
Name: | us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAmortizedCostAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- References No definition available. + Details
Name: | us-gaap_AvailableForSaleSecuritiesDebtMaturitiesFairValueAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amortized cost of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), with single maturity date and allocated without single maturity date, maturing in next fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach). + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 3 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=121645371&loc=d3e27198-111563 + Details
Name: | us-gaap_AvailableForSaleSecuritiesDebtMaturitiesWithinOneYearAmortizedCost
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Fair value of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), with single maturity date and allocated without single maturity date, maturing in next fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach). + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 320 -Section 50 -Paragraph 3A -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=120252992&loc=SL120269850-112803 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 3 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=121645371&loc=d3e27198-111563 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (d) -URI http://asc.fasb.org/extlink&oid=121645371&loc=d3e27161-111563 + Details
Name: | us-gaap_AvailableForSaleSecuritiesDebtMaturitiesWithinOneYearFairValue
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale). + References Reference 1: 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 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 326 -SubTopic 30 -Section 45 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=121558606&loc=SL82898722-210454 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 45 -Paragraph 1 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=121553693&loc=d3e26610-111562 Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (aa) -URI http://asc.fasb.org/extlink&oid=121645371&loc=d3e27161-111563 + Details
Name: | us-gaap_AvailableForSaleSecuritiesDebtSecurities
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Details
Name: | us-gaap_FinancialInstrumentAxis=us-gaap_USTreasurySecuritiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancialInstrumentAxis=us-gaap_USGovernmentAgenciesShorttermDebtSecuritiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancialInstrumentAxis=syn_MortgageBackedSecuritiesIssuedByUSGovernmentAgenciesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancialInstrumentAxis=us-gaap_MortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEnterprisesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancialInstrumentAxis=syn_CollateralizedMortgageObligationsIssuedByUSGovernmentSponsoredEnterprisesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancialInstrumentAxis=syn_CommercialmortgagebackedsecuritiesissuedbyU.S.GovernmentsponsoredagenciesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancialInstrumentAxis=us-gaap_CorporateDebtSecuritiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |