Long-Term Debt (Tables)

9 Months Ended

Sep. 30, 2016

Debt Disclosure [Abstract]

Long-Term Debt

	September 30,			December 31,			September 30,
	2016			2015			2015
	(Dollars in Thousands)
6.6% Senior Notes, due 2018	$	299,388		$	299,113		$	299,020
7% Debentures, due 2025		124,068			124,002			123,981
6.25% Senior Notes, due 2037		227,961			227,917			227,907
4.25 % Senior Notes, due 2024		395,115			394,690			394,575
Floating Rate Notes, due 2017, interest rate of 1.94%,      1.71% and 1.38% at September 30, 2016, December 31, 2015      and September 30, 2015, respectively		298,750			298,868			298,731
Term Loan Facility, due 2018, interest rate of 1.90%, 1.86% and 1.72%      at September 30, 2016, December 31, 2015 and September 30,      2015, respectively		209,096			222,521			225,433
Trade Receivable Facility, interest rate of 1.22% and 0.90% at      September 30, 2016 and September 30, 2015, respectively		210,000			—			130,000
Other notes		457			1,663			1,124
Total debt		1,764,835			1,568,774			1,700,771
Less: Current maturities		(228,025	)		(18,713	)		(147,003	)
Long-term debt	$	1,536,810		$	1,550,061		$	1,553,768