Valuation Techniques, Significant Unobservable Inputs, and Quantitative Information (Detail) - Fair Value, Inputs, Level 3 $ in Millions	12 Months Ended
	Dec. 31, 2015 USD ($)
Auction Rate Securities | Group Two
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Valuation Technique	Discounted Cash Flow
Fair Value, Measurements, Recurring | Auction Rate Securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Assets, fair value	$ 17.1
Fair Value, Measurements, Recurring | Auction Rate Securities | Group One
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Valuation Technique	Discounted Cash Flow
Unobservable Inputs	Remaining lives
Fair Value, Measurements, Recurring | Auction Rate Securities | Group Two
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Unobservable Inputs	Discount rates
Fair Value, Measurements, Recurring | Auction Rate Securities | Lower Limit
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Financial instrument remaining lives	5 months 1 day
Financial instrument discount rate	0.30%
Fair Value, Measurements, Recurring | Auction Rate Securities | Upper Limit
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Financial instrument remaining lives	8 years 7 months 20 days
Financial instrument discount rate	4.40%
Fair Value, Measurements, Recurring | Visa Conversion Rate Swap
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Financial liabilities, fair value	$ 10.8
Fair Value, Measurements, Recurring | Visa Conversion Rate Swap | Group One
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Valuation Technique	Discounted Cash Flow
Unobservable Inputs	Visa Class A Appreciation
Fair Value, Measurements, Recurring | Visa Conversion Rate Swap | Group Two
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Unobservable Inputs	Conversion Rate
Fair Value, Measurements, Recurring | Visa Conversion Rate Swap | Group Three
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Unobservable Inputs	Expected Duration
Fair Value, Measurements, Recurring | Visa Conversion Rate Swap | Lower Limit
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Financial instrument, Visa Class A Appreciation	9.50%
Financial instrument, conversion rate	161.00%
Financial instrument, expected conversion rate	1 year 6 months
Fair Value, Measurements, Recurring | Visa Conversion Rate Swap | Upper Limit
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Financial instrument, Visa Class A Appreciation	15.00%
Financial instrument, conversion rate	165.00%
Financial instrument, expected conversion rate	4 years 6 months