Debt (Tables)

6 Months Ended

Jun. 30, 2018

Debt Instrument [Line Items]

Schedule of Debt [Table Text Block]

Long-term Debt consisted of the following: 

	(in thousands)	Jun 30, 2018			Dec 31, 2017
4.650% Senior Notes due 2024		$	500,000		$	500,000
6.000% Senior Notes due 2028		300,000			—
Term Loan Facility		—			300,000
Fair value of interest rate swaps on $200 million of principal		(9,405		)	(2,990		)
Unamortized debt issuance costs		(8,367		)	(4,698		)
Revolving Credit Facility		—			—
Long-term Debt		$	782,228		$	792,312