Consolidated Condensed Statements of Comprehensive Income - 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 income (loss)	$ (355)	$ 6,554	$ 29,270	$ 40,469
Other comprehensive (loss) income, gross of tax:
Foreign currency translation adjustments (loss) gain	(3,266)	13,251	(14,519)	42,051
Unrealized gain (loss) on foreign currency derivative securities	1,753	(1,234)	2,304	2,541
Unrealized gain (loss) on commodity derivative securities		136	(218)	184
Other comprehensive (loss) income, gross of tax	(1,513)	12,153	(12,433)	44,776
Other comprehensive (loss) income, related tax effect:
Cumulative effect of accounting change due to ASU 2018-02			(40)
Foreign currency translation adjustments (loss) gain	15	(49)	(217)	(158)
Unrealized gain (loss) on foreign currency derivative securities	(536)	331	(684)	(683)
Unrealized gain (loss) on commodity derivative securities		(50)	(59)	(67)
Other comprehensive (loss) income, related tax effect	(521)	232	(1,000)	(908)
Other comprehensive (loss) income, net of tax	(2,034)	12,385	(13,433)	43,868
Comprehensive (loss) income	$ (2,389)	$ 18,939	$ 15,837	$ 84,337