Long-Term Debt (Long-Term Debt) (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Debt Instrument [Line Items]
Total debt	$ 3,632,692	$ 2,157,285
Less - current portion	(1,650)	(2,127)
Less - debt issuance costs	(14,282)	(8,031)
Long-term debt and notes payable	3,616,760	2,147,127
Credit Agreement [Member] | Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Total debt	310,582
Credit Agreement [Member] | Term Loan Facility [Member]
Debt Instrument [Line Items]
Total debt	$ 1,637,500
Prior Credit Agreement [Member] | Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Total debt		390,000
Prior Credit Agreement [Member] | Term Loan Facility [Member]
Debt Instrument [Line Items]
Total debt		800,000
Senior Notes due 2016 [Member] | Senior Notes [Member]
Debt Instrument [Line Items]
Total debt		$ 100,000
Interest rate	3.30%	3.30%
Senior Notes due 2018 [Member] | Senior Notes [Member]
Debt Instrument [Line Items]
Total debt	$ 50,000	$ 50,000
Interest rate	4.00%	4.00%
Senior Notes due 2019 [Member] | Senior Notes [Member]
Debt Instrument [Line Items]
Total debt	$ 175,000	$ 175,000
Interest rate	5.25%	5.25%
Senior Notes due 2021 [Member] | Senior Notes [Member]
Debt Instrument [Line Items]
Total debt	$ 100,000	$ 100,000
Interest rate	4.64%	4.64%
New Senior Notes due 2021 [Member] | Senior Notes [Member]
Debt Instrument [Line Items]
Total debt	$ 150,000
Interest rate	2.39%
Senior Notes due 2022 [Member] | Senior Notes [Member]
Debt Instrument [Line Items]
Total debt	$ 125,000	$ 125,000
Interest rate	3.09%	3.09%
Senior Notes due 2023 [Member] | Senior Notes [Member]
Debt Instrument [Line Items]
Total debt	$ 200,000
Interest rate	2.75%
Senior Notes due 2025 [Member] | Senior Notes [Member]
Debt Instrument [Line Items]
Total debt	$ 375,000	$ 375,000
Interest rate	3.41%	3.41%
Senior Notes due 2026 [Member] | Senior Notes [Member]
Debt Instrument [Line Items]
Total debt	$ 400,000
Interest rate	3.03%
Tax-Exempt Bonds [Member]
Debt Instrument [Line Items]
Total debt	$ 95,430	$ 31,430
Notes Payable to Sellers and Other Third Parties [Member]
Debt Instrument [Line Items]
Debt, maturity date range, start	2017
Debt, maturity date range, end	2036	2036
Notes Payable to Sellers and Other Third Parties [Member] | Minimum [Member]
Debt Instrument [Line Items]
Interest rate	3.00%
Notes Payable to Sellers and Other Third Parties [Member] | Maximum [Member]
Debt Instrument [Line Items]
Interest rate	24.81%
Notes Payable to Sellers and Other Third Parties [Member] | Senior Notes [Member]
Debt Instrument [Line Items]
Total debt	$ 14,180	$ 10,855