Product Warranties (Tables)

9 Months Ended

Sep. 30, 2015

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 2015 and 2014, including customer satisfaction settlements, were as follows:

(Thousands of dollars)
	2015			2014
Balance at January 1	$	27,723		$	26,755
Charges to expense	28,021			25,250
Settlements	(27,182		)	(26,297		)
Balance at September 30	$	28,562		$	25,708