Debt (Tables)

9 Months Ended

Sep. 30, 2011

Debt [Abstract]

Consolidated Debt

	December 31, 2010		September 30, 2011		Weighted-Average Interest Rate  at September 30, 2011 (1)
Revolving credit facility	$	15,000	$	—	—
$250.0 million of 6.45% Notes due 2014	249,786		249,829		6.3%
$250.0 million of 5.65% Notes due 2016	252,466		252,144		5.7%
$250.0 million of 6.40% Notes due 2018	259,125		263,994		5.1%
$550.0 million of 6.55% Notes due 2019	581,890		579,372		5.9%
$550.0 million of 4.25% Notes due 2021	298,932		559,138		4.2%
$250.0 million of 6.40% Notes due 2037	248,949		248,960		6.3%
Total debt	$	1,906,148	$	2,153,437

(1) Weighted-average interest rate includes the impact of outstanding interest rate swaps, the amortization/accretion of discounts and premiums and the amortization/accretion of gains and losses realized on historical cash flow and fair value hedges (see Note 9—Derivative Financial Instruments for detailed information regarding interest rate swaps).