Financial Instruments (Tables)

12 Months Ended

Dec. 31, 2017

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:

	2017				2016
	Carrying Amount		Fair Value		Carrying Amount		Fair Value
	(Dollars in thousands)
Assets:
Cash and cash equivalents	$	53,533	$	53,533	$	24,690	$	24,690
Derivative instruments (other current assets)	1,150		1,150		1,094		1,094
Liabilities:
Bank debt	$	903,945	$	903,945	$	771,192	$	771,192
5% Notes	280,000		281,691		500,000		510,130
5½% Notes	300,000		308,301		300,000		312,750
4¾% Notes	300,000		309,390		—		—
3¼% Notes	780,325		813,793		—		—
Derivative instruments (accrued liabilities)	115		115		244		244