Condensed Consolidated Statements of Operations (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Income Statement [Abstract]
Net sales	$ 127,427	$ 110,550	$ 242,504	$ 214,066
Operating costs and expenses:
Costs of products sold (excluding depreciation and amortization)	108,576	92,052	203,333	176,833
Selling and administrative	14,814	15,053	30,287	30,430
Depreciation and amortization	5,769	5,646	11,674	11,568
Gain on disposal of assets	(106)	(1)	(61)	(1)
Total operating expenses	129,053	112,750	245,233	218,830
Loss from operations	(1,626)	(2,200)	(2,729)	(4,764)
Other income (expense):
Investment-related income	43	22	67	71
Interest expense	(1,020)	(728)	(1,893)	(1,905)
Other – net	451	570	3,351	(315)
Total other income (expense)	(526)	(136)	1,525	(2,149)
Loss before income taxes and equity income in joint venture	(2,152)	(2,336)	(1,204)	(6,913)
Income tax (provision) benefit	(548)	102	(107)	(33)
Equity income in joint venture	0	485	0	535
Net loss	(2,700)	(1,749)	(1,311)	(6,411)
Less: Net income attributable to noncontrolling interest	294	164	742	285
Net loss attributable to Ampco-Pittsburgh shareholders	$ (2,994)	$ (1,913)	$ (2,053)	$ (6,696)
Net loss per common share attributable to Ampco-Pittsburgh:
Basic	$ (0.24)	$ (0.16)	$ (0.17)	$ (0.54)
Diluted	(0.24)	(0.16)	(0.17)	(0.54)
Cash dividends declared per share	$ 0.00	$ 0.00	$ 0.00	$ 0.09
Weighted average number of common shares outstanding:
Basic	12,439	12,327	12,401	12,299
Diluted	12,439	12,327	12,401	12,299