Long-Term Debt (Detail) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2012	Dec. 31, 2011
Debt Instrument [Line Items]
Long-term debt	$ 1,297,150	$ 1,384,639
Less: current portion of total debt	286,636	100,526
Long-term portion of total debt	1,010,514	1,284,113
Obligations under capital leases
Debt Instrument [Line Items]
Long-term debt	4,435	4,679
$1 billion revolver weighted average rate 1.71%, due in 2016
Debt Instrument [Line Items]
Long-term debt	231,804	527,884
$100 million Private Placement notes 5.64%, due in 2015
Debt Instrument [Line Items]
Long-term debt	100,000	100,000
$200 million Term Loan with rate of 1.09% due Dec 2012
Debt Instrument [Line Items]
Long-term debt	200,000	0
$175 million Private Placement notes 3.89%, due in 2017
Debt Instrument [Line Items]
Long-term debt	175,000	175,000
$225 million Private Placement notes 4.47%, due in 2020
Debt Instrument [Line Items]
Long-term debt	225,000	225,000
Acquisition notes weighted average rate of 2.96% and weighted average maturity of 3.9 years
Debt Instrument [Line Items]
Long-term debt	220,096	240,138
Foreign bank debt weighted average rate 5.94% and Weighted average maturity of 2.0 years
Debt Instrument [Line Items]
Long-term debt	$ 140,815	$ 111,938