Condensed Consolidated Statements of Comprehensive Income (Loss) (Unaudited) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Statement Of Income And Comprehensive Income [Abstract]
Net loss	$ (2,700)	$ (1,749)	$ (1,311)	$ (6,411)
Adjustments for changes in:
Foreign currency translation	(6,197)	4,926	(3,699)	7,178
Unrecognized employee benefit costs (including effects of foreign currency translation)	692	(866)	279	(1,121)
Unrealized holding gains on marketable securities	0	102	0	287
Fair value of cash flow hedges	(6)	15	(321)	239
Reclassification adjustments for items included in net loss:
Amortization of unrecognized employee benefit costs	64	783	194	1,516
Realized gains from sale of marketable securities	0	0	0	(6)
Realized gains from settlement of cash flow hedges	(92)	(167)	(301)	(322)
Other comprehensive (loss) income	(5,539)	4,793	(3,848)	7,771
Comprehensive (loss) income	(8,239)	3,044	(5,159)	1,360
Less: Comprehensive income attributable to noncontrolling interest	109	92	708	216
Comprehensive (loss) income attributable to Ampco-Pittsburgh	$ (8,348)	$ 2,952	$ (5,867)	$ 1,144

Other comprehensive income loss gross adjustments net of tax.

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