Condensed Consolidated Statements of Operations (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Income Statement [Abstract]
Net sales	$ 75,674	$ 90,872	$ 241,515	$ 300,885
Operating costs and expenses:
Costs of products sold (excluding depreciation and amortization)	59,461	75,475	189,604	250,232
Selling and administrative	11,445	12,365	33,474	40,179
Depreciation and amortization	4,511	4,502	13,863	14,411
Impairment charge	0	0	0	10,082
Loss (gain) on disposal of assets	79	(130)	131	(67)
Total operating expenses	75,496	92,212	237,072	314,837
Income (loss) from continuing operations	178	(1,340)	4,443	(13,952)
Other income (expense):
Investment-related income	1,215	19	1,327	1,419
Interest expense	(1,018)	(1,541)	(3,228)	(4,035)
Other income – net	1,493	2,068	2,510	4,289
Total other income (expense)	1,690	546	609	1,673
Income (loss) from continuing operations before income taxes	1,868	(794)	5,052	(12,279)
Income tax (provision) benefit	(630)	(429)	1,649	(1,716)
Net income (loss) from continuing operations	1,238	(1,223)	6,701	(13,995)
Loss from discontinued operations, net of tax	0	(3,398)	0	(9,031)
Net income (loss)	1,238	(4,621)	6,701	(23,026)
Less: Net income attributable to noncontrolling interest	270	434	923	1,035
Net income (loss) attributable to Ampco-Pittsburgh	$ 968	$ (5,055)	$ 5,778	$ (24,061)
Net income (loss) from continuing operations per share attributable to Ampco-Pittsburgh common shareholders:
Basic	$ 0.07	$ (0.13)	$ 0.45	$ (1.19)
Diluted	0.07	(0.13)	0.43	(1.19)
Loss from discontinued operations, net of tax, per share attributable to Ampco-Pittsburgh common shareholders:
Basic	0.00	(0.27)	0.00	(0.72)
Diluted	0.00	(0.27)	0.00	(0.72)
Net income (loss) per share attributable to Ampco-Pittsburgh common shareholders:
Basic	0.07	(0.40)	0.45	(1.91)
Diluted	$ 0.07	$ (0.40)	$ 0.43	$ (1.91)
Weighted average number of common shares outstanding:
Basic	13,343	12,640	12,915	12,572
Diluted	14,454	12,640	13,585	12,572