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	Sep. 30, 2021	Dec. 31, 2020
Investments, Unrealized Loss Position [Line Items]
Less than 12 months Unrealized Losses	$ 6,339	$ 10,317
Total Unrealized Losses	6,339	10,317
Less than 12 months Fair Value	44,412	94,401
12 Months or more Fair Value	917
Total Fair Value	45,329	94,401
Fixed maturities
Investments, Unrealized Loss Position [Line Items]
Less than 12 months Unrealized Losses		1,332
Total Unrealized Losses		1,332
Less than 12 months Fair Value		18,392
12 Months or more Fair Value	917
Total Fair Value	917	18,392
Fixed maturities | U.S. governmental securities
Investments, Unrealized Loss Position [Line Items]
12 Months or more Fair Value	297
Total Fair Value	297
Fixed maturities | Corporate debt securities
Investments, Unrealized Loss Position [Line Items]
12 Months or more Fair Value	620
Total Fair Value	620
Fixed maturities | Other Debt Securities
Investments, Unrealized Loss Position [Line Items]
Less than 12 months Unrealized Losses		1,332
Total Unrealized Losses		1,332
Less than 12 months Fair Value		18,392
Total Fair Value		18,392
Mutual funds - debt securities
Investments, Unrealized Loss Position [Line Items]
Less than 12 months Fair Value	7
Total Fair Value	7
Mutual funds - equity securities
Investments, Unrealized Loss Position [Line Items]
Less than 12 months Unrealized Losses		154
Total Unrealized Losses		154
Less than 12 months Fair Value		128
Total Fair Value		128
Other investment funds
Investments, Unrealized Loss Position [Line Items]
Less than 12 months Unrealized Losses	4,752	8,812
Total Unrealized Losses	4,752	8,812
Less than 12 months Fair Value	39,305	75,799
Total Fair Value	39,305	75,799
Equity securities
Investments, Unrealized Loss Position [Line Items]
Less than 12 months Unrealized Losses	1,587	19
Total Unrealized Losses	1,587	19
Less than 12 months Fair Value	5,100	82
Total Fair Value	$ 5,100	$ 82