Net Sales and Revenue Recognition (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Product Information [Line Items]
Net Sales	$ 221,962	$ 201,183	$ 434,017	$ 396,092
North America [Member]
Product Information [Line Items]
Net Sales	97,392	90,331	189,212	177,672
EMEA [Member]
Product Information [Line Items]
Net Sales	60,166	54,507	122,221	108,434
Asia Pacific [Member]
Product Information [Line Items]
Net Sales	55,348	47,724	104,125	92,874
South America [Member]
Product Information [Line Items]
Net Sales	9,056	$ 8,621	18,459	$ 17,112
Transferred At Point In Time [Member]
Product Information [Line Items]
Net Sales	216,676		423,828
Transferred At Point In Time [Member] | North America [Member]
Product Information [Line Items]
Net Sales	94,562		183,548
Transferred At Point In Time [Member] | EMEA [Member]
Product Information [Line Items]
Net Sales	60,110		122,109
Transferred At Point In Time [Member] | Asia Pacific [Member]
Product Information [Line Items]
Net Sales	53,017		99,865
Transferred At Point In Time [Member] | South America [Member]
Product Information [Line Items]
Net Sales	8,987		18,306
Transferred Over Time [Member]
Product Information [Line Items]
Net Sales	5,286		10,189
Transferred Over Time [Member] | North America [Member]
Product Information [Line Items]
Net Sales	2,830		5,664
Transferred Over Time [Member] | EMEA [Member]
Product Information [Line Items]
Net Sales	56		112
Transferred Over Time [Member] | Asia Pacific [Member]
Product Information [Line Items]
Net Sales	2,331		4,260
Transferred Over Time [Member] | South America [Member]
Product Information [Line Items]
Net Sales	69		153
Primary Metals [Member]
Product Information [Line Items]
Net Sales	101,715		206,482
Primary Metals [Member] | North America [Member]
Product Information [Line Items]
Net Sales	35,453		76,726
Primary Metals [Member] | EMEA [Member]
Product Information [Line Items]
Net Sales	26,187		53,504
Primary Metals [Member] | Asia Pacific [Member]
Product Information [Line Items]
Net Sales	35,040		65,918
Primary Metals [Member] | South America [Member]
Product Information [Line Items]
Net Sales	5,035		10,334
Metalworking [Member]
Product Information [Line Items]
Net Sales	99,601		188,992
Metalworking [Member] | North America [Member]
Product Information [Line Items]
Net Sales	46,646		83,520
Metalworking [Member] | EMEA [Member]
Product Information [Line Items]
Net Sales	29,762		60,923
Metalworking [Member] | Asia Pacific [Member]
Product Information [Line Items]
Net Sales	19,328		36,901
Metalworking [Member] | South America [Member]
Product Information [Line Items]
Net Sales	3,865		7,648
Coatings and Other [Member]
Product Information [Line Items]
Net Sales	20,646		38,543
Coatings and Other [Member] | North America [Member]
Product Information [Line Items]
Net Sales	15,293		28,966
Coatings and Other [Member] | EMEA [Member]
Product Information [Line Items]
Net Sales	4,217		7,794
Coatings and Other [Member] | Asia Pacific [Member]
Product Information [Line Items]
Net Sales	980		1,306
Coatings and Other [Member] | South America [Member]
Product Information [Line Items]
Net Sales	$ 156		$ 477