Contractual Maturities of Debt Securities Held in Merchandise Trusts (Detail) - Variable Interest Entity, Primary Beneficiary - Merchandise Trusts - Fixed maturities $ in Thousands	Jun. 30, 2016 USD ($)
Investments Classified by Contractual Maturity Date [Line Items]
Less than 1 year	$ 171
1 year through 5 years	7,214
6 years through 10 years	1,410
More than 10 years	0
U.S. governmental securities
Investments Classified by Contractual Maturity Date [Line Items]
Less than 1 year	11
1 year through 5 years	12
6 years through 10 years	82
More than 10 years	0
Corporate debt securities
Investments Classified by Contractual Maturity Date [Line Items]
1 year through 5 years	7,202
6 years through 10 years	1,328
More than 10 years	0
Other debt securities
Investments Classified by Contractual Maturity Date [Line Items]
Less than 1 year	160
More than 10 years	$ 0