Long-term Debt - Long-Term Debt (Detail) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012
Debt Instrument [Line Items]
Long Term Debt	$ 2,154,872	$ 2,160,854
Less current maturities	(33,315)	(33,134)
Long-term debt, excluding current maturities	2,121,557	2,127,720
Senior Credit Facility [Member]
Debt Instrument [Line Items]
Long Term Debt	376,539	384,664
7 7/8% Senior Subordinated Notes [Member]
Debt Instrument [Line Items]
Long Term Debt	400,000	400,000
5 7/8% Senior Subordinated Notes [Member]
Debt Instrument [Line Items]
Long Term Debt	500,000	500,000
5% Senior Subordinated Notes [Member]
Debt Instrument [Line Items]
Long Term Debt	535,000	535,000
9 3/4% Senior Notes [Member]
Debt Instrument [Line Items]
Long Term Debt	341,164	339,121
Other notes with various rates and terms [Member]
Debt Instrument [Line Items]
Long Term Debt	$ 2,169	$ 2,069