Description of Business and Significant Accounting Policies (Tables)

12 Months Ended

Dec. 31, 2017

Allowance for doubtful accounts activity

Activity in our allowance for doubtful accounts was comprised of the following for the periods indicated:



	Year ended December 31,
	2017			2016			2015
	(In thousands)
Beginning balance	$	1,091		$	1,856		$	1,947
Additions	1,720			368			17
Deductions	(319		)	(1,133		)	(108		)
Ending balance	$	2,492		$	1,091		$	1,856

Property, plant and equipment estimated useful lives

Depreciation of property, plant and equipment is recognized on a straight-line basis over the following estimated useful lives:



Class of assets		Useful life
Buildings and improvements		5 to 40 years
Machinery, equipment, and furniture and fixtures		3 to 10 years
Leasehold improvements		Shorter of asset life or term of lease

Schedule of antidilutive securities excluded from computation of EPS

The following table presents instruments which were not dilutive and were excluded from the computation of diluted EPS in each period, as well as the weighted average dilutive common stock equivalent shares which were included in the computation of diluted EPS:



	Year ended December 31,
	2017	2016	2015
	(In thousands)
Non-dilutive instruments	13	45	15
Dilutive common stock equivalents	125	95	154