XML 81 R71.htm IDEA: XBRL DOCUMENT
v3.5.0.2

Mortgage Servicing Rights - Additional Information (Detail) - USD ($) | 6 Months Ended |
--- | --- | ---
Jun. 30, 2016 | Dec. 31, 2015
Finite-Lived Intangible Assets [Line Items] |  |
Mortgage servicing rights | $ 193,994,000 | $ 247,734,000
Mortgage Receivable |  |
Finite-Lived Intangible Assets [Line Items] |  |
Unpaid principal balance of loans serviced for others | 25,100,000,000 | $ 24,200,000,000
Impairment of intangible assets | $ 0 |

X
- Definition Amount of loans serviced for others. + References No definition available. + Details
Name: | nyb_AmountOfLoansServicedForOthers
Namespace Prefix: | nyb_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

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_FiniteLivedIntangibleAssetsLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition The amount of impairment loss recognized in the period resulting from the write-down of the carrying amount of a finite-lived intangible asset to fair value. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 350 -SubTopic 30 -Section 50 -Paragraph 3 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=66006027&loc=d3e16373-109275 + Details
Name: | us-gaap_ImpairmentOfIntangibleAssetsFinitelived
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Fair value of an asset representing net future revenue from contractually specified servicing fees, late charges, and other ancillary revenues, in excess of future costs related to servicing arrangements. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 860 -SubTopic 50 -Section 50 -Paragraph 3 -Subparagraph (a)(1) -URI http://asc.fasb.org/extlink&oid=68078379&loc=d3e122625-111746 + Details
Name: | us-gaap_ServicingAssetAtFairValueAmount
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Details
Name: | us-gaap_FinancingReceivablePortfolioSegmentAxis=us-gaap_MortgageReceivablesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |