Condensed Consolidated Statements of Operations (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Income Statement [Abstract]
Net sales	$ 90,872	$ 98,824	$ 300,885	$ 323,610
Operating costs and expenses:
Costs of products sold (excluding depreciation and amortization)	75,475	82,007	250,232	268,500
Selling and administrative	12,365	13,999	40,179	43,128
Depreciation and amortization	4,502	5,361	14,411	16,409
Impairment charge	0	0	10,082	0
(Gain) loss on disposal of assets	(130)	304	(67)	386
Total operating expenses	92,212	101,671	314,837	328,423
Loss from continuing operations	(1,340)	(2,847)	(13,952)	(4,813)
Other income (expense):
Investment-related income	19	433	1,419	500
Interest expense	(1,541)	(1,054)	(4,035)	(2,947)
Other – net	2,068	1,255	4,289	5,597
Total other income (expense)	546	634	1,673	3,150
Loss from continuing operations before income taxes	(794)	(2,213)	(12,279)	(1,663)
Income tax provision	(429)	(800)	(1,716)	(883)
Net loss from continuing operations	(1,223)	(3,013)	(13,995)	(2,546)
Loss from discontinued operations, net of tax	(3,398)	(3,443)	(9,031)	(5,221)
Net loss	(4,621)	(6,456)	(23,026)	(7,767)
Less: Net income attributable to noncontrolling interest	434	583	1,035	1,325
Net loss attributable to Ampco-Pittsburgh	$ (5,055)	$ (7,039)	$ (24,061)	$ (9,092)
Net loss from continuing operations per common share:
Basic	$ (0.10)	$ (0.24)	$ (1.11)	$ (0.20)
Diluted	(0.10)	(0.24)	(1.11)	(0.20)
Loss from discontinued operations, net of tax, per common share:
Basic	(0.27)	(0.28)	(0.72)	(0.42)
Diluted	(0.27)	(0.28)	(0.72)	(0.42)
Net loss per common share attributable to Ampco-Pittsburgh:
Basic	(0.40)	(0.56)	(1.91)	(0.73)
Diluted	$ (0.40)	$ (0.56)	$ (1.91)	$ (0.73)
Weighted average number of common shares outstanding:
Basic	12,640	12,494	12,572	12,432
Diluted	12,640	12,494	12,572	12,432