CONDENSED CONSOLIDATED STATEMENTS OF EQUITY (Unaudited) - USD ($) $ in Thousands	Total	Common Stock Issued	Common Stock Treasury	Additional Paid-in Capital	Retained Earnings	Accumulated Other Comprehensive Loss	Noncontrolling Interests
Beginning balance at Dec. 31, 2019	$ 789,659	$ 143,400	$ (838,893)	$ 200,595	$ 1,824,100	$ (587,622)	$ 48,079
Increase (Decrease) in Stockholders' Equity
Net income (loss)	1,227				141		1,086
Total other comprehensive income	(30,002)					(28,854)	(1,148)
Vesting of restricted stock units and other stock grants, net	(889)	230	(889)	(230)
Vesting of performance share units, net	(3,205)	589	(3,205)	(589)
Amortization of unearned portion of stock-based compensation, net of forfeitures	2,080			2,080
Ending balance at Mar. 31, 2020	758,870	144,219	(842,987)	201,856	1,824,241	(616,476)	48,017
Beginning balance at Dec. 31, 2019	789,659	143,400	(838,893)	200,595	1,824,100	(587,622)	48,079
Increase (Decrease) in Stockholders' Equity
Net income (loss)	(8,228)
Total other comprehensive income	(16,971)
Ending balance at Jun. 30, 2020	764,516	144,245	(843,003)	203,916	1,813,639	(603,618)	49,337
Beginning balance at Mar. 31, 2020	758,870	144,219	(842,987)	201,856	1,824,241	(616,476)	48,017
Increase (Decrease) in Stockholders' Equity
Net income (loss)	(9,455)				(10,602)		1,147
Total other comprehensive income	13,031					12,858	173
Stock appreciation rights exercised, net	(16)	8	(16)	(8)
Vesting of performance share units, net	0	18	0	(18)
Amortization of unearned portion of stock-based compensation, net of forfeitures	2,086			2,086
Ending balance at Jun. 30, 2020	764,516	144,245	(843,003)	203,916	1,813,639	(603,618)	49,337
Beginning balance at Dec. 31, 2020	713,399	144,288	(843,230)	204,078	1,797,759	(645,741)	56,245
Increase (Decrease) in Stockholders' Equity
Net income (loss)	1,565				135		1,430
Total other comprehensive income	1,229					2,295	(1,066)
Stock appreciation rights exercised, net	(70)	9	(70)	(9)
Vesting of restricted stock units and other stock grants, net	(1,850)	312	(1,850)	(312)
Vesting of performance share units, net	(1,032)	155	(1,032)	(155)
Amortization of unearned portion of stock-based compensation, net of forfeitures	3,342			3,342
Ending balance at Mar. 31, 2021	716,583	144,764	(846,182)	206,944	1,797,894	(643,446)	56,609
Beginning balance at Dec. 31, 2020	713,399	144,288	(843,230)	204,078	1,797,759	(645,741)	56,245
Increase (Decrease) in Stockholders' Equity
Net income (loss)	16,645
Total other comprehensive income	19,142
Noncontrolling Interest, Decrease from Distributions to Noncontrolling Interest Holders	(3,094)						(3,094)
Ending balance at Jun. 30, 2021	749,383	144,836	(846,401)	209,992	1,811,282	(626,206)	55,880
Beginning balance at Mar. 31, 2021	716,583	144,764	(846,182)	206,944	1,797,894	(643,446)	56,609
Increase (Decrease) in Stockholders' Equity
Net income (loss)	15,080				13,388		1,692
Total other comprehensive income	17,913					17,240	673
Stock appreciation rights exercised, net	(219)	28	(219)	(28)
Vesting of restricted stock units and other stock grants, net	0	44		(44)
Amortization of unearned portion of stock-based compensation, net of forfeitures	3,120			3,120
Ending balance at Jun. 30, 2021	$ 749,383	$ 144,836	$ (846,401)	$ 209,992	$ 1,811,282	$ (626,206)	$ 55,880