Condensed Consolidated Statements of Comprehensive Income (Loss) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Statement of Comprehensive Income [Abstract]
Consolidated net income (loss)	$ (13,941)	$ 8,715	$ 64,695	$ 66,158
Other comprehensive income (loss), net of tax:
Foreign currency translation adjustments	(6,900)	8,190	(8,797)	(8,375)
Benefit plans	498	0	301	2,236
Total other comprehensive income (loss), net of tax	(6,402)	8,190	(8,496)	(6,139)
Comprehensive income (loss)	(20,343)	16,905	56,199	60,019
Less: Comprehensive income (loss) attributable to noncontrolling interest in subsidiaries, net of tax	(3,314)	890	15,947	17,231
Comprehensive income (loss) attributable to common stockholders	$ (17,029)	$ 16,015	$ 40,252	$ 42,788