Debt and Credit Agreements (Details 2) $ in Thousands		12 Months Ended
	Sep. 12, 2013	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)	Dec. 31, 2013 USD ($)
Debt Instrument [Line Items]
Long-term Debt		$ 880,835	$ 854,897
Less: current maturities		(25,084)	(25,188)
Total Long-term Debt		855,751	829,709
Cash payments for interest on all debt		$ 44,400	44,200	$ 50,100
Minimum consolidated interest coverage ratio, numerator		3
Minimum consolidated interest coverage ratio, denominator		1
Maturities of Long-term Debt [Abstract]
2017		$ 45,294
2018		479,012
2019		331,225
2020		189
Senior Notes | 5.75% notes due May 15, 2018
Debt Instrument [Line Items]
Long-term Debt		$ 449,005	$ 448,626
Stated interest rate		5.75%	5.75%
Redemption price (percent)		101.00%
Senior Notes | 2.7% notes due October 15, 2015
Debt Instrument [Line Items]
Long-term Debt		$ 0	$ 249,733
Stated interest rate		2.70%	2.70%
Debt Instrument, Redemption Price, Percentage		101.00%
Term Loan | Term Loan Facility 2015
Debt Instrument [Line Items]
Long-term Debt		$ 250,000	$ 0
Minimum consolidated interest coverage ratio, numerator	3.0
Other financing payable in varying amounts due principally through 2018 with a weighted-average interest rate of 2.7% and 9.4% at December 31, 2012 and 2011, respectively
Debt Instrument [Line Items]
Long-term Debt		$ 38,830	$ 156,538
Weighted average interest rate		5.60%	4.00%
Revolving Credit Facility
Debt Instrument [Line Items]
Long-term Debt		$ 143,000	$ 0
Line of credit
Debt Instrument [Line Items]
Minimum consolidated interest coverage ratio, numerator	4.0
Minimum consolidated interest coverage ratio, denominator	1
Debt Issuance Cost		$ 600
After December 31, 2016 | Line of credit
Debt Instrument [Line Items]
Minimum consolidated interest coverage ratio, numerator	3.75
After June 30, 2017 | Line of credit
Debt Instrument [Line Items]
Minimum consolidated interest coverage ratio, numerator	3.5