Consolidated Statements of Changes in Equity - USD ($) $ in Thousands	Total	Common Shares	Additional Paid-In Capital	Retained Earnings	Accumulated Other Comprehensive Income (Loss)	Treasury Stock	Non-Controlling Interest
Balance at Beginning of Period at Dec. 31, 2018	$ 160,900	$ 1,148	$ 57,438	$ 156,130	$ (5,456)	$ (52,501)	$ 4,141
Stock based-awards	14,341		6,626			7,715
Repurchase of common shares	(1,091)					(1,091)
Dividends paid	(48,769)			(48,769)
Amortization of deferred pension costs, net of tax	(16)				(16)
Interest rate swaps, net of tax	(887)				(887)
Net income (loss)	68,014			67,924			90
Balance at End of Period at Jun. 30, 2019	$ 192,492	1,148	64,064	175,285	(6,359)	(45,877)	4,231
Cash Dividends per Share	$ 1.10
Balance at Beginning of Period at Mar. 31, 2019	$ 187,353	1,148	65,084	172,266	(5,795)	(49,538)	4,188
Stock based-awards	3,245		(1,020)			4,265
Repurchase of common shares	(604)					(604)
Dividends paid	(24,395)			(24,395)
Amortization of deferred pension costs, net of tax	(9)				(9)
Interest rate swaps, net of tax	(555)				(555)
Net income (loss)	27,457			27,414			43
Balance at End of Period at Jun. 30, 2019	$ 192,492	1,148	64,064	175,285	(6,359)	(45,877)	4,231
Cash Dividends per Share	$ 0.55
Balance at Beginning of Period at Dec. 31, 2019	$ 182,140	1,148	51,872	160,539	(6,330)	(29,364)	4,275
Stock based-awards	13,395		9,029			4,366
Repurchase of common shares	(1,436)					(1,436)
Dividends paid	(11,556)			(11,556)
Non-controlling interest dividends	(355)						(355)
Interest rate swaps, net of tax	(2,028)				(2,028)
Net income (loss)	(114,013)			(114,137)			124
Balance at End of Period at Jun. 30, 2020	$ 66,147	1,148	60,901	34,846	(8,358)	(26,434)	4,044
Cash Dividends per Share	$ 0.26
Balance at Beginning of Period at Mar. 31, 2020	$ 70,074	1,148	60,982	41,007	(8,239)	(29,182)	4,358
Stock based-awards	2,865		(81)			2,946
Repurchase of common shares	(198)					(198)
Dividends paid	(445)			(445)
Non-controlling interest dividends	(355)						(355)
Interest rate swaps, net of tax	(119)				(119)
Net income (loss)	(5,675)			(5,716)			41
Balance at End of Period at Jun. 30, 2020	$ 66,147	$ 1,148	$ 60,901	$ 34,846	$ (8,358)	$ (26,434)	$ 4,044
Cash Dividends per Share	$ 0.01