Long-term Debt - Long-Term Debt (Detail) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Debt Instrument [Line Items]
Debt	$ 2,423,027	$ 2,378,152
Debt, Less current maturities	(22,500)	(39,375)
Debt, excluding current maturities	2,400,527	2,338,777
Deferred financing costs	31,173	28,969
Deferred financing costs, Less current maturities	(5,029)	(5,459)
Deferred financing costs, excluding current maturities	26,144	23,510
Debt, net of deferred financing costs	2,391,854	2,349,183
Debt, net of deferred financing costs, Less current maturities	(17,471)	(33,916)
Debt, net of deferred financing costs, excluding current maturities	2,374,383	2,315,267
Senior Credit Facility [Member]
Debt Instrument [Line Items]
Debt	478,000	433,125
Deferred financing costs	8,535	4,769
Debt, net of deferred financing costs	469,465	428,356
5 7/8% Senior Subordinated Notes [Member]
Debt Instrument [Line Items]
Debt	500,000	500,000
Deferred financing costs	6,470	7,071
Debt, net of deferred financing costs	493,530	492,929
5% Senior Subordinated Notes [Member]
Debt Instrument [Line Items]
Debt	535,000	535,000
Deferred financing costs	5,323	5,709
Debt, net of deferred financing costs	529,677	529,291
5 3/8% Senior Notes [Member]
Debt Instrument [Line Items]
Debt	510,000	510,000
Deferred financing costs	5,326	5,662
Debt, net of deferred financing costs	504,674	504,338
5 3/4% Senior Notes [Member]
Debt Instrument [Line Items]
Debt	400,000	400,000
Deferred financing costs	5,519	5,758
Debt, net of deferred financing costs	394,481	394,242
Other Notes with Various Rates and Terms [Member]
Debt Instrument [Line Items]
Debt	27	27
Debt, net of deferred financing costs	$ 27	$ 27