Long-Term Debt (Long-Term Debt) (Detail) (USD $) In Thousands, unless otherwise specified	6 Months Ended		12 Months Ended
	Jun. 30, 2014		Dec. 31, 2013
Debt Instrument [Line Items]
Total debt	$ 1,935,293		$ 2,072,975
Less - current portion	(4,031)		(5,385)
Long-term debt and notes payable	1,931,262		2,067,590
Revolver Under Credit Facility [Member]
Debt Instrument [Line Items]
Total debt	632,000	[1]	727,100	[1]
Interest rate, minimum	1.52%	[1]
Interest rate, maximum	3.75%	[1]
Term Loan Facility [Member]
Debt Instrument [Line Items]
Total debt	660,000	[1]	700,000	[1]
Interest rate, minimum	1.65%	[1]
Interest rate, maximum	2.04%	[1]
Senior Notes due 2015 [Member]
Debt Instrument [Line Items]
Total debt	175,000		175,000
Interest rate	6.22%		6.22%
Debt instrument maturity date year	2015		2015
Senior Notes due 2016 [Member]
Debt Instrument [Line Items]
Total debt	100,000		100,000
Interest rate	3.30%		3.30%
Debt instrument maturity date year	2016		2016
Senior Notes due 2018 [Member]
Debt Instrument [Line Items]
Total debt	50,000		50,000
Interest rate	4.00%		4.00%
Debt instrument maturity date year	2018		2018
Senior Notes due 2019 [Member]
Debt Instrument [Line Items]
Total debt	175,000		175,000
Interest rate	5.25%		5.25%
Debt instrument maturity date year	2019		2019
Senior Notes due 2021 [Member]
Debt Instrument [Line Items]
Total debt	100,000		100,000
Interest rate	4.64%		4.64%
Debt instrument maturity date year	2021		2021
Tax-exempt Bonds [Member]
Debt Instrument [Line Items]
Total debt	32,825	[1]	33,030	[1]
Interest rate, minimum	0.06%	[1]
Interest rate, maximum	0.18%	[1]
2.50% to 10.9% Notes Payable to Sellers and Other Third Parties [Member]
Debt Instrument [Line Items]
Total debt	$ 10,468	[1]	$ 12,845	[1]
Interest rate, minimum	2.50%	[1]
Interest rate, maximum	10.90%	[1]

[1] Interest rates in the table above represent the range of interest rates incurred during the six month period ended June 30, 2014.