DEBT - Additional Information (Detail) (USD $)	Mar. 31, 2014	Dec. 31, 2013
Debt Instrument [Line Items]
Guaranteed loan, loan balance	$ 4,800,000
$1 billion senior credit facility weighted average rate 1.82%, due in 2016
Debt Instrument [Line Items]
Maximum borrowing capacity of line of credit facility	1,000,000,000.0
Senior letters of credit facility, committed to outstanding letters of credit	151,200,000	155,000,000
Senior letters of credit facility, unused portion	630,500,000	572,600,000
$100 million private placement notes 5.64%, due in 2015
Debt Instrument [Line Items]
Long-term debt, face amount	100,000,000.0
$175 million private placement notes 3.89%, due in 2017
Debt Instrument [Line Items]
Long-term debt, face amount	175,000,000.0
$125 million private placement notes 2.68%, due in 2019
Debt Instrument [Line Items]
Long-term debt, face amount	125,000,000.0
$225 million private placement notes 4.47%, due in 2020
Debt Instrument [Line Items]
Long-term debt, face amount	225,000,000.0
$125 million private placement notes 3.26%, due in 2022
Debt Instrument [Line Items]
Long-term debt, face amount	125,000,000.0
Other Assets [Member]
Debt Instrument [Line Items]
Loan receivable from customer	$ 15,500,000