XML 61 R47.htm IDEA: XBRL DOCUMENT
v3.10.0.1

Securities - Additional Information (Detail) $ in Thousands | 12 Months Ended
--- | ---
Dec. 31, 2018 USD ($) Investment | Dec. 31, 2017 USD ($) Investment | Dec. 31, 2016 USD ($)
Schedule of Investments [Line Items] |  |  |
Federal Home Loan Bank stock, at cost | $ 644,590 | $ 603,819 |
Amortized cost from sales of held to maturity securities |  | 521,000 |
Proceeds from sales of held to maturity securities |  | 547,925 | $ 1,297
Gross realized gains from sales of held to maturity securities |  | 26,900 |
Securities transferred from held to maturity to available for sale |  | 3,040,305 |
Unrealized gain on securities transferred from held to maturity to available for sale |  | 82,800 |
Investment securities designated as having a continuous loss position for twelve months or more, unrealized losses | $ 22,500 | $ 10,100 |
Investment securities designated as having a continuous loss position for twelve months or more, percentage below collective amortized cost | 2.90% | 8.50% |
Investment securities designated as having a continuous loss position for twelve months or more, amortized cost | $ 782,400 | $ 118,200 |
Capital trust notes |  |  |
Schedule of Investments [Line Items] |  |  |
Number of investment securities designated as having a continuous loss position for twelve months or more | Investment | 5 | 5 |
Municipal bonds |  |  |
Schedule of Investments [Line Items] |  |  |
Number of investment securities designated as having a continuous loss position for twelve months or more | Investment | 3 | 2 |
Mutual Fund |  |  |
Schedule of Investments [Line Items] |  |  |
Number of investment securities designated as having a continuous loss position for twelve months or more | Investment | 1 | 1 |

X
- Definition Number of Securities, Continuous Unrealized Loss Position More Than Twelve Months + References No definition available. + Details
Name: | nyb_NumberOfSecuritiesContinuousUnrealizedLossPositionMoreThanTwelveMonths
Namespace Prefix: | nyb_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | instant

X
- Definition Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Aggregate Losses. + References No definition available. + Details
Name: | nyb_SecuritiesContinuousUnrealizedLossPositionTwelveMonthsOrLongerAggregateLosses
Namespace Prefix: | nyb_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Amortized Cost. + References No definition available. + Details
Name: | nyb_SecuritiesContinuousUnrealizedLossPositionTwelveMonthsOrLongerAmortizedCost
Namespace Prefix: | nyb_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Percentage Below Amortized Cost. + References No definition available. + Details
Name: | nyb_SecuritiesContinuousUnrealizedLossPositionTwelveMonthsOrLongerPercentageBelowAmortizedCost
Namespace Prefix: | nyb_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Federal Home Loan Bank (FHLB) stock represents an equity interest in a FHLB. It does not have a readily determinable fair value because its ownership is restricted and it lacks a market (liquidity). + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 325 -Section 45 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=75031641&loc=d3e63345-112809 + Details
Name: | us-gaap_FederalHomeLoanBankStock
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount, before other-than-temporary impairment (OTTI) accretion, of investment in debt securities measured at amortized cost (held-to-maturity). + References No definition available. + Details
Name: | us-gaap_HeldToMaturitySecuritiesAmortizedCostBeforeOtherThanTemporaryImpairment
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount of gain (loss) on sale of investment in debt security measured at amortized cost (held-to-maturity), including other-than-temporary impairment (OTTI). + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 10 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=82897076&loc=d3e27405-111563 + Details
Name: | us-gaap_HeldToMaturitySecuritiesSoldSecurityRealizedGainLoss
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Amount after tax, before reclassification adjustments, of unrealized holding gain (loss) related to transfers of securities into the available-for-sale classification and out of the held-to-maturity classification. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 35 -Paragraph 10 -Subparagraph (c),(d) -URI http://asc.fasb.org/extlink&oid=115930623&loc=d3e24820-111560 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 220 -SubTopic 10 -Section 45 -Paragraph 15 -URI http://asc.fasb.org/extlink&oid=114867106&loc=d3e689-108580 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 220 -SubTopic 10 -Section 45 -Paragraph 11 -URI http://asc.fasb.org/extlink&oid=114867106&loc=d3e637-108580 + Details
Name: | us-gaap_OtherComprehensiveIncomeLossTransfersFromHeldToMaturityToAvailableForSaleSecuritiesNetOfTax
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition The cash inflow associated with the sale of securities that had been designated as held-to-maturity. Excludes proceeds from maturities, prepayments and calls by the issuer. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 45 -Paragraph 11 -URI http://asc.fasb.org/extlink&oid=109979856&loc=d3e26853-111562 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 12 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=109223946&loc=d3e3179-108585 + Details
Name: | us-gaap_ProceedsFromSaleOfHeldToMaturitySecurities
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References No definition available. + Details
Name: | us-gaap_ScheduleOfInvestmentsLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Value of investments transferred to the entity's investments in noncash transactions. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 50 -Paragraph 4 -URI http://asc.fasb.org/extlink&oid=98513485&loc=d3e4313-108586 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 50 -Paragraph 5 -URI http://asc.fasb.org/extlink&oid=98513485&loc=d3e4332-108586 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 50 -Paragraph 3 -URI http://asc.fasb.org/extlink&oid=98513485&loc=d3e4304-108586 + Details
Name: | us-gaap_TransferToInvestments
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Details
Name: | us-gaap_InvestmentTypeAxis=us-gaap_CorporateNoteSecuritiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_InvestmentTypeAxis=us-gaap_MunicipalBondsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_InvestmentTypeAxis=us-gaap_MutualFundMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |