Fair value of financial instruments - Fair value, assets measure on recurring basis, unobservable inputs (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended	4 Months Ended	9 Months Ended
Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Net unrealized gain on mortgage loans	$ 17,670	$ 0	$ 25,963
Fair value, inputs, level 3 [Member] \| Loans receivable [Member] \| Residential mortgage [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	163,520		0
Investment in mortgage loans	475,998		644,163
Net unrealized gain on mortgage loans	17,670		25,963
Net realized gain on mortgage loans	1,909		4,015
Mortgage loan payments	(999)		(2,616)
Mortgage loan dispositions	(9,996)		(19,024)
Transfer of mortgage loans to real estate owned	(6,199)		(10,598)
Ending balance	641,903		641,903
Net unrealized gain on mortgage loans	17,670		25,963
Accumulated net unrealized gains on mortgage loans at fair value still held	$ 25,963		$ 25,963

Fair Value Measurement with Unobservable Inputs Reconciliation Recurring Basis, Asset, Principal and Interest Receipts

No definition available.

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- Definition

Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Realized Gain (Loss) Included in Earnings

+ References

No definition available.

+ Details

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- Definition

Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Sales and Settlements

+ References

No definition available.

+ Details

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Namespace Prefix:	resi_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfer to Real Estate Owned

+ References

No definition available.

+ Details

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Namespace Prefix:	resi_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Unrealized Gain (Loss) Included in Earnings

+ References

No definition available.

+ Details

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Namespace Prefix:	resi_
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- Definition

Investments, Gross Unrealized Gain (Loss)

+ References

No definition available.

+ Details

Name:	resi_InvestmentsGrossUnrealizedGainLoss
Namespace Prefix:	resi_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Details

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Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Purchases that have taken place during the period in relation to assets measured at fair value and categorized within Level 3 of the fair value hierarchy.

+ References

+ Details

Name:	us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetPurchases
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

This element represents an asset measured at fair value using significant unobservable inputs (Level 3) which is required for reconciliation purposes of beginning and ending balances.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 820

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (c)

-URI http://asc.fasb.org/extlink&oid=7578670&loc=d3e19207-110258

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 157

-Paragraph 32

-Subparagraph c

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

The net change in the difference between the fair value and the carrying value, or in the comparative fair values, of investments, not including unrealized gains or losses on securities separately or otherwise categorized as trading, available-for-sale, or held-to-maturity, held at each balance sheet date and included in earnings for the period.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 95

-Paragraph 28

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 28

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=6943989&loc=d3e3602-108585

+ Details

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Namespace Prefix:	us-gaap_
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Balance Type:	credit
Period Type:	duration