DEBT - Additional Information (Detail) - USD ($)	Mar. 31, 2016	Dec. 31, 2015
$1.20 billion senior credit facility weighted average rate 1.87%, due in 2019
Debt Instrument [Line Items]
Maximum borrowing capacity of line of credit facility	$ 1,200,000,000
Revolving credit facility, amount committed to outstanding letters of credit	159,800,000	$ 160,400,000
Revolving credit facility, unused portion	584,300,000	$ 685,800,000
Term loan maturing in August 2020
Debt Instrument [Line Items]
Maximum borrowing capacity of line of credit facility	1,080,000,000
$175 million private placement notes 3.89%, due in 2017
Debt Instrument [Line Items]
Long-term debt, face amount	175,000,000
$125 million private placement notes 2.68%, due in 2019
Debt Instrument [Line Items]
Long-term debt, face amount	125,000,000
$225 million private placement notes 4.47%, due in 2020
Debt Instrument [Line Items]
Long-term debt, face amount	225,000,000
$150 million private placement notes 2.89%, due in 2021
Debt Instrument [Line Items]
Long-term debt, face amount	150,000,000
$125 million private placement notes 3.26%, due in 2022
Debt Instrument [Line Items]
Long-term debt, face amount	125,000,000
$200 million private placement notes 2.72%, due in 2022
Debt Instrument [Line Items]
Long-term debt, face amount	200,000,000
$100 million private placement notes 2.79%, due in 2023
Debt Instrument [Line Items]
Long-term debt, face amount	100,000,000
$150 million private placement notes 3.18%, due in 2023
Debt Instrument [Line Items]
Long-term debt, face amount	$ 150,000,000