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	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, 2020	713,399	144,288	(843,230)	204,078	1,797,759	(645,741)	56,245
Increase (Decrease) in Stockholders' Equity
Net income	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