Condensed Consolidated Statements of Comprehensive Income (Loss) (Unaudited) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Statement Of Income And Comprehensive Income [Abstract]
Net loss	$ (6,456)	$ (1,903)	$ (7,767)	$ (8,314)
Adjustments for changes in:
Foreign currency translation	(1,102)	3,526	(4,801)	10,704
Unrecognized employee benefit costs (including effects of foreign currency translation)	138	(652)	417	(1,773)
Unrealized holding gains on marketable securities	0	136	0	423
Fair value of cash flow hedges	(198)	217	(519)	456
Reclassification adjustments for items included in net loss:
Amortization of unrecognized employee benefit costs	(42)	945	152	2,461
Realized gains from sale of marketable securities	0	(19)	0	(25)
Realized losses (gains) from settlement of cash flow hedges	46	(150)	(255)	(472)
Other comprehensive (loss) income	(1,158)	4,003	(5,006)	11,774
Comprehensive (loss) income	(7,614)	2,100	(12,773)	3,460
Less: Comprehensive income attributable to noncontrolling interest	794	440	1,502	656
Comprehensive (loss) income attributable to Ampco-Pittsburgh	$ (8,408)	$ 1,660	$ (14,275)	$ 2,804

Other comprehensive income loss gross adjustments net of tax.

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