OTHER COMPREHENSIVE LOSS - Reclassifications Out of Accumulated Other Comprehensive Loss (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Net impairment losses on available-for-sale debt securities	$ (50)	$ (12,231)	$ (6,687)
Total before tax	190,638	61,983	130,259
Income tax expense	10,970	4,973	(37,030)
Net Income Loss	201,608	66,956	93,229
Reclassification out of Accumulated Other Comprehensive Income [Member] | Accumulated Net Investment Gain (Loss) Attributable to Parent [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Net (loss) gain on sale of investments	(34)	371	6,104
Net impairment losses on available-for-sale debt securities	(50)	(12,231)	(6,687)
Total before tax	(84)	(11,860)	(583)
Income tax expense	0	0	0
Net Income Loss	$ (84)	$ (11,860)	$ (583)