Fair Value Measurements (Table)

9 Months Ended

Sep. 30, 2013

Fair Value Disclosures

Fair value measurements

		Level within the Fair Value Hierarchy	September 30, 2013				December 31, 2012
			Book Value			Fair Value	Book Value		Fair Value
(Dollars in thousands)
Cash and cash equivalents		1	$	183,101	$	183,101	$	378,358	$	378,358
Short-term investments
	U.S. Treasury Notes	1		45,162		45,162		100,676		100,676
Long-term investments
	U.S. Treasury Notes	1		40,099		40,154		50,305		50,339
Long-term debt
	6.95% Senior Notes	1		342,000		330,509		342,000		376,610
	6.7% Senior Notes	2		532,383		512,221		532,194		582,744