Reclassifications of Accumulated Other Comprehensive Income (Parenthetical) (Detail) - USD ($) $ in Thousands		3 Months Ended		6 Months Ended
	Mar. 15, 2018	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Net realized capital gains		$ 6,462	$ 9,268	$ 50,967	$ 68,919
Ares
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Net realized capital gains				45,700
Ares | Insurance Segment
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Net realized capital gains	$ 45,700			$ 45,700