DISCLOSURES REGARDING FAIR VALUES OF FINANCIAL INSTRUMENTS - Balance Sheet Location (Detail) (USD $) In Thousands, unless otherwise specified							6 Months Ended
	Jun. 30, 2014	Dec. 31, 2013	Jun. 30, 2014 Carrying Amount [Member]	Dec. 31, 2013 Carrying Amount [Member]	Jun. 30, 2014 Fair Value [Member]	Dec. 31, 2013 Fair Value [Member]	Jun. 30, 2014 Maximum [Member]
Fair value, balance sheet grouping [Line Items]
Investment Repurchase Agreement Initial Term							120 days
Financial assets [Abstract]
Residential mortgage loans	$ 13,711,400	$ 13,475,874	$ 5,920	$ 6,898	$ 6,000	$ 7,000
Interest rate swap agreements at fair value	78	5,005	78	5,005	78	5,005
Financial liabilities [Abstract]
Repurchase arrangements with initial terms of greater than 120 days, Fair Value			557,320	36,299	557,500	36,300
Unsecured borrowings			100,000	100,000	100,600	101,000
Interest rate swap agreements			$ 21,979	$ 11,304	$ 21,979	$ 11,304