INTERIM CONSOLIDATED STATEMENTS OF CHANGES IN SHAREHOLDERS' EQUITY - USD ($) shares in Thousands, $ in Thousands	Total	Common Shares	Additional Paid-in Capital	Retained Earnings	Accumulated Other Comprehensive Loss
Balance at Dec. 31, 2020	$ 601,027	$ 65,800	$ 345,696	$ 217,106	$ (27,575)
Balance (in shares) at Dec. 31, 2020		65,868
Shares issued on grants of performance share units		$ 120	(120)
Shares issued on grants of performance share units (in shares)		120
Stock compensation expense	610		610
Net income	5,933			5,933
Dividends declared	(4,289)			(4,289)
Other comprehensive loss	(35,643)				(35,643)
Balance at Mar. 31, 2021	567,638	$ 65,920	346,186	218,750	(63,218)
Balance (in shares) at Mar. 31, 2021		65,988
Balance at Dec. 31, 2021	$ 694,024	$ 65,988	347,902	370,927	(90,793)
Balance (in shares) at Dec. 31, 2021	66,037	66,037
Shares issued on grants of performance share units		$ 95	(95)
Shares issued on grants of performance share units (in shares)		95
Stock compensation expense	$ 949		949
Net income	88,897			88,897
Dividends declared	(4,960)			(4,960)
Other comprehensive loss	(10,576)				(10,576)
Balance at Mar. 31, 2022	$ 768,334	$ 66,083	$ 348,756	$ 454,864	$ (101,369)
Balance (in shares) at Mar. 31, 2022	66,132	66,132