Product Warranties (Tables)

9 Months Ended

Sep. 30, 2017

Product Warranties Disclosures [Abstract]

Company's accrual for product warranty claims

Changes in the Company’s accrual for product warranty claims during the first nine months of 2017 and 2016, including customer satisfaction settlements, were as follows:

(Thousands of dollars)
	2017			2016
Balance at January 1	$	34,419		$	31,878
Charges to expense	27,802			25,391
Settlements	(41,408		)	(25,330		)
Acquisition	107,321
Balance at September 30	$	128,134		$	31,939