MERCHANDISE TRUSTS - Aging of Unrealized Losses on Investments in Fixed Maturities and Equity Securities Held in Merchandise Trusts (Detail) - Variable Interest Entity, Primary Beneficiary - Merchandise Trusts - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Investments, Unrealized Loss Position [Line Items]
Less than 12 months Unrealized Losses	$ 2,185	$ 9,819
12 Months or more Unrealized Losses	289	1,333
Total Unrealized Losses	2,474	11,152
Less than 12 months Fair Value	96,785	216,168
12 Months or more Fair Value	1,484	3,374
Total Fair Value	98,269	219,542
Fixed maturities
Investments, Unrealized Loss Position [Line Items]
Less than 12 months Unrealized Losses	9	2
12 Months or more Unrealized Losses	277	473
Total Unrealized Losses	286	475
Less than 12 months Fair Value	85	103
12 Months or more Fair Value	1,310	792
Total Fair Value	1,395	895
Fixed maturities | U.S. governmental securities
Investments, Unrealized Loss Position [Line Items]
12 Months or more Unrealized Losses	132	147
Total Unrealized Losses	132	147
12 Months or more Fair Value	604	243
Total Fair Value	604	243
Fixed maturities | Corporate debt securities
Investments, Unrealized Loss Position [Line Items]
Less than 12 months Unrealized Losses	9	2
12 Months or more Unrealized Losses	145	326
Total Unrealized Losses	154	328
Less than 12 months Fair Value	85	103
12 Months or more Fair Value	706	549
Total Fair Value	791	652
Mutual funds - debt securities
Investments, Unrealized Loss Position [Line Items]
Less than 12 months Unrealized Losses	5	2,011
12 Months or more Unrealized Losses	12	634
Total Unrealized Losses	17	2,645
Less than 12 months Fair Value	149	46,005
12 Months or more Fair Value	174	1,195
Total Fair Value	323	47,200
Mutual funds - equity securities
Investments, Unrealized Loss Position [Line Items]
Less than 12 months Unrealized Losses		18
Total Unrealized Losses		18
Less than 12 months Fair Value	7	131
Total Fair Value	7	131
Other investment funds
Investments, Unrealized Loss Position [Line Items]
Less than 12 months Unrealized Losses	2,083	7,784
Total Unrealized Losses	2,083	7,784
Less than 12 months Fair Value	94,501	169,929
Total Fair Value	94,501	169,929
Equity securities
Investments, Unrealized Loss Position [Line Items]
Less than 12 months Unrealized Losses	88
12 Months or more Unrealized Losses		213
Total Unrealized Losses	88	213
Less than 12 months Fair Value	2,043
12 Months or more Fair Value		597
Total Fair Value	$ 2,043	597
Other invested assets
Investments, Unrealized Loss Position [Line Items]
Less than 12 months Unrealized Losses		4
12 Months or more Unrealized Losses		13
Total Unrealized Losses		17
12 Months or more Fair Value		790
Total Fair Value		$ 790