Condensed Consolidated Statements of Changes in Shareholders' Equity (Unaudited) - USD ($) $ in Thousands	Total	Common Shares	Preferred Shares	Additional Paid-in Capital	Retained Earnings	Accumulated Other Comprehensive Income (Loss)
Balance (in shares) at Dec. 31, 2018		29,988,460
Balance at Dec. 31, 2018	$ 709,241	$ 6	$ 0	$ 645,310	$ 79,753	$ (15,828)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net (loss) income	22,728				22,728
Other comprehensive income (loss)	20,260					20,260
Dividends	(9,144)				(9,144)
Exercise of stock options (in shares)		98,975
Exercise of stock options	2,632			2,632
Vesting of RSUs (in shares)		74,610
Vesting of RSUs	(1,374)			(1,374)
Compensation expense under share incentive plans	1,674			1,674
Balance (in shares) at Mar. 31, 2019		30,162,045
Balance at Mar. 31, 2019	$ 754,297	$ 6	0	648,242	101,617	4,432
Balance (in shares) at Dec. 31, 2019	30,424,391	30,424,391
Balance at Dec. 31, 2019	$ 778,581	$ 6	0	657,875	89,586	31,114
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net (loss) income	(36,815)				(36,815)
Other comprehensive income (loss)	(3,919)					(3,919)
Dividends	(9,267)				(9,267)
Vesting of RSUs (in shares)		96,037
Vesting of RSUs	(2,038)			(2,038)
Compensation expense under share incentive plans	$ 1,867			1,867
Balance (in shares) at Mar. 31, 2020	30,520,428	30,520,428
Balance at Mar. 31, 2020	$ 720,317	$ 6	$ 0	$ 657,704	$ 35,412	$ 27,195