| REAL ESTATE SECURITIES - Geographic Distribution of Collateral Securing Newcastle's CMBS and ABS (Details 4) (USD $) In Thousands, unless otherwise specified | Sep. 30, 2014
 CMBS [Member] | Sep. 30, 2014
 CMBS [Member]
 Western US [Member] | Sep. 30, 2014
 CMBS [Member]
 Northeastern US [Member] | Sep. 30, 2014
 CMBS [Member]
 Southeastern US [Member] | Sep. 30, 2014
 CMBS [Member]
 Midwestern US [Member] | Sep. 30, 2013
 CMBS [Member]
 Southwestern US [Member] | Sep. 30, 2014
 CMBS [Member]
 Other Locations [Member] | Sep. 30, 2014
 CMBS [Member]
 Foreign Locations [Member] | Sep. 30, 2014
 ABS [Member] | Sep. 30, 2014
 ABS [Member]
 Western US [Member] | Sep. 30, 2014
 ABS [Member]
 Northeastern US [Member] | Sep. 30, 2014
 ABS [Member]
 Southeastern US [Member] | Sep. 30, 2014
 ABS [Member]
 Midwestern US [Member] | Sep. 30, 2014
 ABS [Member]
 Southwestern US [Member] | Sep. 30, 2014
 ABS [Member]
 Other Locations [Member] | |||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Principal balance | $ 240,403 | [1] | $ 40,073 | $ 51,078 | $ 47,340 | $ 33,008 | $ 51,696 | $ 10,825 | $ 6,383 | $ 95,577 | $ 29,606 | $ 23,194 | $ 19,477 | $ 12,310 | $ 10,382 | $ 608 | ||
| Percentage of principal balance | 100.00% | 16.70% | 21.20% | 19.70% | 13.70% | 21.50% | 4.50% | 2.70% | 100.00% | 31.00% | 24.20% | 20.40% | 12.90% | 10.90% | 0.60% | |||
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- Definition For investments which are quantified by principal amount, the principle balance held at close of period. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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- Definition Percent of net assets at close of period. For schedules of investments that are categorized, each category has a percent of net assets for the aggregated value of the Investments in the category. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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