RECLASSIFICATION FROM ACCUMULATED OTHER COMPREHENSIVE INCOME INTO NET INCOME - Summary of Amounts Reclassified out of Accumulated Other Comprehensive Income into Net Income (Details) (USD $) In Thousands, unless otherwise specified	1 Months Ended	3 Months Ended								12 Months Ended
	Jan. 31, 2014	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Gain on settlement of securities										$ (35,487)	$ (52,657)
Other-than-temporary impairment (OTTI) on securities	1,000	448	0	615	328	1,237	0	3,756	0	1,391	4,993	0
Total reclassifications		(50,928)	(152,098)	(182,208)	(56,865)	(80,181)	(63,145)	(109,222)	(13,075)	(442,099)	(265,623)	(41,247)
Reclassification out of Accumulated Other Comprehensive Income [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Gain on settlement of securities										(65,701)	(52,657)	0
Other-than-temporary impairment (OTTI) on securities										1,391	4,993	0
Total reclassifications										$ (64,310)	$ (47,664)	$ 0