Financial Instruments (Tables)

12 Months Ended

Dec. 31, 2015

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:

	2015				2014
	Carrying Amount		Fair Value		Carrying Amount		Fair Value
	(Dollars in thousands)
Assets:
Cash and cash equivalents	$	99,945	$	99,945	$	222,591	$	222,591
Liabilities:
Bank debt	$	725,818	$	725,818	$	798,963	$	798,963
5½% Notes	300,000		309,189		300,000		307,500
5% Notes	500,000		510,055		500,000		500,715
Interest rate swap agreements	771		771		1,196		1,196
Natural gas swap agreements	813		813		746		746