Long-Term Debt (Tables)

3 Months Ended

Mar. 31, 2012

Long-Term Debt [Abstract]

Long-term debt

	March 31, 2012			December 31, 2011
Revolver under credit facility, bearing interest ranging from 1.64% to 3.65%*	$	230,000		$	519,000
2015 Notes, bearing interest at 6.22%		175,000			175,000
2016 Notes, bearing interest at 3.30%		100,000			100,000
2018 Notes, bearing interest at 4.00%		50,000			50,000
2019 Notes, bearing interest at 5.25%		175,000			175,000
2021 Notes, bearing interest at 4.64%		100,000			100,000
Tax-exempt bonds, bearing interest ranging from 0.12% to 0.32%*		38,460			38,460
Notes payable to sellers in connection with acquisitions, bearing interest at 2.50% to 10.35%*		16,548			18,356
Notes payable to third parties, bearing interest at 6.7% to 10.9%*		2,784			2,841
		887,792			1,178,657
Less — current portion		(4,618	)		(5,899	)
	$	883,174		$	1,172,758

* Interest rates in the table above represent the range of interest rates incurred during the three month period ended March 31, 2012.