Financial Instruments (Tables)

3 Months Ended

Mar. 31, 2016

Investments, All Other Investments [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 March 31, 2016:

	Carrying Amount		Fair Value
	(Dollars in thousands)
Assets:
Cash and cash equivalents	$	66,614	$	66,614
Liabilities:
Bank debt	$	1,029,629	$	1,029,629
5½% Senior Notes	300,000		312,444
5% Senior Notes	500,000		510,270
Interest rate swap agreements	949		949
Natural gas swap agreements	724		724