XML 68 R54.htm IDEA: XBRL DOCUMENT
v3.8.0.1

Securities - Additional Information (Detail) $ in Thousands | 12 Months Ended
--- | ---
Dec. 31, 2017 USD ($) Investment | Dec. 31, 2016 USD ($) Investment | Dec. 31, 2015 USD ($)
Schedule of Investments [Line Items] |  |  |  |  |
Federal Home Loan Bank stock, at cost | [1] | $ 603,819 | $ 590,934 |  |
Amortized cost from sales of held to maturity securities |  | 521,000 | 3,721,368 | [2] |
Proceeds from sales of held to maturity securities |  | 547,925 | 1,297 |  | $ 44,104
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 |  | $ 10,100 | $ 14,100 |  |
Investment securities designated as having a continuous loss position for twelve months or more, percentage below collective amortized cost |  | 8.50% | 32.20% |  |
Investment securities designated as having a continuous loss position for twelve months or more, amortized cost |  | $ 43,700 | $ 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 |  |
Mortgage-Related Securities |  |  |  |  |
Schedule of Investments [Line Items] |  |  |  |  |
Number of investment securities designated as having a continuous loss position for twelve months or more | Investment |  | 6 |  |  |
[1] | Carrying value and estimated fair value are at cost.
[2] | Held-to-maturity securities are reported at a carrying amount equal to amortized cost less the non-credit portion of OTTI recorded in AOCL. At December 31, 2016, the non-credit portion of OTTI recorded in AOCL was $8.6 million (before taxes).

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://www.xbrl.org/2003/role/presentationRef -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 investments in debt securities classified as 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 This item represents the gain (loss) realized on the sale of held-to-maturity securities disposed of during the period. Additionally, this item may include, if not separately presented, any losses recognized for other than temporary impairments (OTTI) of the subject investments in debt securities which are being or have been recognized in earnings during the period. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -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://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 35 -Paragraph 10 -Subparagraph (c),(d) -URI http://asc.fasb.org/extlink&oid=82895926&loc=d3e24820-111560 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 220 -SubTopic 10 -Section 45 -Paragraph 15 -URI http://asc.fasb.org/extlink&oid=84228862&loc=d3e689-108580 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 220 -SubTopic 10 -Section 45 -Paragraph 11 -URI http://asc.fasb.org/extlink&oid=84228862&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://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 45 -Paragraph 11 -URI http://asc.fasb.org/extlink&oid=82896770&loc=d3e26853-111562 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 12 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=98514028&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://www.xbrl.org/2003/role/presentationRef -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 2: http://www.xbrl.org/2003/role/presentationRef -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 3: http://www.xbrl.org/2003/role/presentationRef -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_MortgageBackedSecuritiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |