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
CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (LOSS)
Net income including non-controlling interests	$ 31,757	$ 58,506	$ 202,170	$ 141,074
Unrealized gain (loss) on derivatives designated and qualifying as cash flow hedges, net of tax of $707 and $1,493 in the three and nine months ended September 30, 2021; $337 and $(62) in the three and nine months ended September 30, 2020	2,876	639	5,412	(622)
Defined benefit pension plan activity, net of tax of $18,759 and $19,005 in the three and nine months ended September 30, 2021; $(776) and $(8,303) in the three and nine months ended September 30, 2020	55,558	(1,304)	58,916	(23,731)
Currency translation adjustment	(19,120)	13,039	(28,284)	(43,101)
Other comprehensive income (loss):	39,314	12,374	36,044	(67,454)
Comprehensive income	71,071	70,880	238,214	73,620
Comprehensive income (loss) attributable to non-controlling interests	(58)	62	(196)	14
Comprehensive income (loss) attributable to shareholders	$ 71,129	$ 70,818	$ 238,410	$ 73,606