CONDENSED CONSOLIDATED STATEMENTS OF EQUITY - USD ($) $ in Thousands	Total	Common Stock Issued	Common Stock Treasury	Additional Paid-in Capital	Retained Earnings	Accumulated Other Comprehensive Loss	Noncontrolling Interests
Balances at Dec. 31, 2016	$ 137,563	$ 140,625	$ (760,391)	$ 172,101	$ 1,150,688	$ (606,722)	$ 41,262
Increase (Decrease) in Stockholders' Equity
Net income	10,137				8,890		1,247
Total other comprehensive income (loss), net of deferred income taxes of $467 and $124 in 2018 and 2017, respectively	17,385					16,999	386
Vesting of restricted stock units and other stock grants, net 102,695 shares and 7,254 shares in 2018 and 2017, respectively	(53)	14	(53)	(14)
Amortization of unearned portion of stock-based compensation, net of forfeitures	3,104			3,104
Balances at Mar. 31, 2017	168,533	140,639	(760,444)	176,297	1,158,869	(589,723)	42,895
Increase (Decrease) in Stockholders' Equity
Adoption of new accounting standards (See Note 2)	397			1,106	(709)
Adoption of new accounting standards (See Note 2)	2,387				3,907	(1,520)
Balances at Dec. 31, 2017	215,165	141,110	(762,079)	180,201	1,157,801	(546,582)	44,714
Increase (Decrease) in Stockholders' Equity
Net income	19,577				17,808		1,769
Sale of subsidiary shares to noncontrolling interest	477						477
Total other comprehensive income (loss), net of deferred income taxes of $467 and $124 in 2018 and 2017, respectively	6,163					4,885	1,278
Stock Appreciation Rights exercised, net 2,560 shares	(26)	5	(26)	(5)
Vesting of restricted stock units and other stock grants, net 102,695 shares and 7,254 shares in 2018 and 2017, respectively	(683)	171	(683)	(171)
Amortization of unearned portion of stock-based compensation, net of forfeitures	3,285			3,285
Balances at Mar. 31, 2018	$ 246,345	$ 141,286	$ (762,788)	$ 183,310	$ 1,179,516	$ (543,217)	$ 48,238