Long-Term Debt (Detail) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2013		Dec. 31, 2012
Debt Instrument [Line Items]
Long-term Debt	$ 2,075,703		$ 2,238,935
Less - current portion	(55,319)		(33,968)
Long-term debt and notes payable	2,020,384		2,204,967
Revolver Under Credit Facility
Debt Instrument [Line Items]
Long-term Debt	635,000	[1]	787,000	[1]
Term Loan Facility
Debt Instrument [Line Items]
Long-term Debt	790,000	[1]	800,000	[1]
6.22% Senior Notes due 2015
Debt Instrument [Line Items]
Long-term Debt	175,000		175,000
3.30% Senior Notes due 2016
Debt Instrument [Line Items]
Long-term Debt	100,000		100,000
4.00% Senior Notes due 2018
Debt Instrument [Line Items]
Long-term Debt	50,000		50,000
5.25% Senior Notes due 2019
Debt Instrument [Line Items]
Long-term Debt	175,000		175,000
4.64% Senior Notes due 2021
Debt Instrument [Line Items]
Long-term Debt	100,000		100,000
Tax-exempt bonds
Debt Instrument [Line Items]
Long-term Debt	35,570	[1]	35,655	[1]
2.5% to 10.9% notes payable to sellers and other third parties
Debt Instrument [Line Items]
Long-term Debt	$ 15,133	[1]	$ 16,280	[1]

[1] Interest rates in the table above represent the range of interest rates incurred during the six month period ended June 30, 2013.