Fair Value Measurements (Tables)

12 Months Ended

Dec. 31, 2013

Fair Value Measurements Tables [Abstract]

Fair Value of Long-Term Debt

		Level 1		Level 2		Level 3		Total
Assets:
Current derivative asset	$	-	$	1,415	$	-	$	1,415
Liabilities:
Current derivative liability	$	-	$	27,291	$	-	$	27,291

		December 31, 2013				December 31, 2012
		Carrying		Estimated		Carrying		Estimated
		Amount		Fair Value		Amount		Fair Value
Long-Term Debt:
5.45% Notes due 2015, issued 2008	$	100,000	$	105,913	$	100,000	$	107,801
7.31% Notes due 2016, issued 2009		62,000		70,228		62,000		72,046
4.98% Notes due 2017, issued 2010		116,000		126,342		116,000		127,109
5.92% Notes due 2018, issued 2008		200,000		226,127		200,000		230,062
5.75% Notes due 2018, issued 2013		450,000		466,946		-		-
7.77% Notes due 2019, issued 2009		173,000		211,877		173,000		219,045
5.50% Notes due 2020, issued 2010		207,000		229,068		207,000		234,552
4.51% Notes due 2020, issued 2010		315,000		323,732		315,000		331,329
5.60% Notes due 2022, issued 2010		87,000		95,736		87,000		98,526
4.66% Notes due 2022, issued 2010		35,000		35,494		35,000		36,361
5.85% Notes due 2025, issued 2010		90,000		99,142		90,000		102,096
4.91% Notes due 2025, issued 2010		175,000		175,744		175,000		179,677
Credit Facility		460,000		460,000		277,000		277,000
	$	2,470,000	$	2,626,349	$	1,837,000	$	2,015,604