Quarterly Information - Quarterly Information - Unaudited (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Quarterly Financial Information Disclosure [Abstract]
Net sales	$ 92,126	$ 82,861	$ 93,301	$ 63,578	$ 55,326	$ 58,094	$ 59,973	$ 65,087	$ 331,866	$ 238,480	$ 272,858
Gross profit	11,454	15,594	15,849	12,473	8,131	9,439	11,776	13,043
Net (loss) income attributable to Ampco-Pittsburgh	$ (43,062)	$ (27,382)	$ (6,486)	$ (2,890)	$ 3,332	$ (1,511)	$ (520)	$ 72	$ (79,820)	$ 1,373	$ (1,187)
Net (loss) income per common share attributable to Ampco-Pittsburgh:
Basic	$ (3.51)	$ (2.23)	$ (0.53)	$ (0.26)	$ 0.32	$ (0.14)	$ (0.05)	$ 0.01	$ (6.68)	$ 0.13	$ (0.11)
Diluted	$ (3.51)	$ (2.23)	$ (0.53)	$ (0.26)	$ 0.32	$ (0.14)	$ (0.05)	$ 0.01	$ (6.68)	$ 0.13	$ (0.11)
Comprehensive (loss) income attributable to Ampco-Pittsburgh	$ (47,972)	$ (22,894)	$ (10,739)	$ (1,501)	$ 8,296	$ (2,250)	$ 2,789	$ 3,692	$ (83,106)	$ 12,527	$ (24,075)