Net Sales and Revenue Recognition (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Product Information [Line Items]
Net sales	$ 205,869	$ 221,962	$ 417,079	$ 434,017
North America [Member]
Product Information [Line Items]
Net sales	94,383	97,392	189,636	189,212
EMEA [Member]
Product Information [Line Items]
Net sales	53,150	60,166	109,438	122,221
Asia Pacific [Member]
Product Information [Line Items]
Net sales	49,827	55,348	100,354	104,125
South America [Member]
Product Information [Line Items]
Net sales	8,509	9,056	17,651	18,459
Transferred At Point In Time [Member]
Product Information [Line Items]
Net sales	201,557	216,676	407,989	423,828
Transferred At Point In Time [Member] | North America [Member]
Product Information [Line Items]
Net sales	91,612	94,562	184,095	183,548
Transferred At Point In Time [Member] | EMEA [Member]
Product Information [Line Items]
Net sales	53,098	60,110	109,332	122,109
Transferred At Point In Time [Member] | Asia Pacific [Member]
Product Information [Line Items]
Net sales	48,406	53,017	97,057	99,865
Transferred At Point In Time [Member] | South America [Member]
Product Information [Line Items]
Net sales	8,441	8,987	17,505	18,306
Transferred Over Time [Member]
Product Information [Line Items]
Net sales	4,312	5,286	9,090	10,189
Transferred Over Time [Member] | North America [Member]
Product Information [Line Items]
Net sales	2,771	2,830	5,541	5,664
Transferred Over Time [Member] | EMEA [Member]
Product Information [Line Items]
Net sales	52	56	106	112
Transferred Over Time [Member] | Asia Pacific [Member]
Product Information [Line Items]
Net sales	1,421	2,331	3,297	4,260
Transferred Over Time [Member] | South America [Member]
Product Information [Line Items]
Net sales	68	69	146	153
Primary Metals [Member]
Product Information [Line Items]
Net sales	99,161	105,369	201,111	206,447
Primary Metals [Member] | North America [Member]
Product Information [Line Items]
Net sales	38,918	39,144	78,603	76,702
Primary Metals [Member] | EMEA [Member]
Product Information [Line Items]
Net sales	24,723	26,173	49,606	53,487
Primary Metals [Member] | Asia Pacific [Member]
Product Information [Line Items]
Net sales	31,041	35,017	63,133	65,924
Primary Metals [Member] | South America [Member]
Product Information [Line Items]
Net sales	4,479	5,035	9,769	10,334
Metalworking [Member]
Product Information [Line Items]
Net sales	87,536	95,931	176,449	188,999
Metalworking [Member] | North America [Member]
Product Information [Line Items]
Net sales	40,698	42,929	81,134	83,518
Metalworking [Member] | EMEA [Member]
Product Information [Line Items]
Net sales	26,740	29,813	54,988	60,983
Metalworking [Member] | Asia Pacific [Member]
Product Information [Line Items]
Net sales	16,470	19,324	32,938	36,850
Metalworking [Member] | South America [Member]
Product Information [Line Items]
Net sales	3,628	3,865	7,389	7,648
Coatings and Other [Member]
Product Information [Line Items]
Net sales	19,172	20,662	39,519	38,571
Coatings and Other [Member] | North America [Member]
Product Information [Line Items]
Net sales	14,767	15,319	29,899	28,992
Coatings and Other [Member] | EMEA [Member]
Product Information [Line Items]
Net sales	1,687	4,180	4,844	7,751
Coatings and Other [Member] | Asia Pacific [Member]
Product Information [Line Items]
Net sales	2,316	1,007	4,283	1,351
Coatings and Other [Member] | South America [Member]
Product Information [Line Items]
Net sales	$ 402	$ 156	$ 493	$ 477