Fair Value Measurement (Tables)

6 Months Ended

Jun. 30, 2018

Fair Value Disclosures [Abstract]

Fair value measured on recurring basis

The fair value hierarchy has three levels based on the reliability of the inputs used to determine the fair value. 

			Fair Value Measurements at June 30, 2018 Using
			Quoted Prices in Active Markets for Identical Assets		Significant Other Observable Inputs		Significant Unobservable Inputs
(In thousands of dollars)	Total		(Level 1)		(Level 2)		(Level 3)
Assets:
Derivative instruments	$	5,662	$	—	$	5,662	$	—
Total Assets	$	5,662	$	—	$	5,662	$	—
Liabilities:
Derivative instruments	$	3,584	$	—	$	3,584	$	—
5.375% Senior notes	506,250		—		506,250		—
3.625% Senior notes	603,721		—		603,721		—
Term loan A	88,541		—		88,541		—
Term loan B	497,784		—		497,784		—
Revolver debt	25,247		—		25,247		—
Total Liabilities	$	1,725,127	$	—	$	1,725,127	$	—

			Fair Value Measurements at December 30, 2017 Using
			Quoted Prices in Active Markets for Identical Assets		Significant Other Observable Inputs		Significant Unobservable Inputs
(In thousands of dollars)	Total		(Level 1)		(Level 2)		(Level 3)
Assets:
Derivative instruments	$	4,346	$	—	$	4,346	$	—
Total Assets	$	4,346	$	—	$	4,346	$	—
Liabilities:
Derivative instruments	$	2,326	$	—	$	2,326	$	—
5.375% Senior notes	513,100		—		513,100		—
4.75% Senior notes	646,681		—		646,681		—
Term loan A	95,883		—		95,883		—
Term loan B	511,616		—		511,616		—
Total Liabilities	$	1,769,606	$	—	$	1,769,606	$	—