Financial Instruments (Tables)

12 Months Ended

Dec. 31, 2013

Fair Value Disclosures [Abstract]

Summary of Carrying Amounts and Estimated Fair Values of Other Financial Instruments

The following table summarizes the carrying amounts and estimated fair values of our other financial instruments at December 31:

	2013				2012
	Carrying Amount		Fair Value		Carrying Amount		Fair Value
	(Dollars in thousands)
Assets:
Cash and cash equivalents	$	160,463	$	160,463	$	465,608	$	465,608
Liabilities:
Bank debt	$	903,836	$	903,836	$	1,171,316	$	1,171,316
5½% Notes	300,000		298,125		—		—
5% Notes	500,000		495,625		500,000		522,500
Interest rate swap agreements	6,895		6,895		13,307		13,307
Natural gas swap agreements	22		22		279		279