Consolidated Statements of Changes in Shareholders' Equity - USD ($) $ in Thousands	Total	Additional Paid-in Capital	Accumulated Other Comprehensive Income, Net of Deferred Income Tax	Retained Earnings	Treasury Shares	Class A Common Shares	Class A Common Shares Treasury Shares	Series A Cumulative Fixed Rate Preferred Shares	Class B Common Shares
Number at Dec. 31, 2019					115,221	10,282,277		0	4,133,366
Class A common shares purchased							4,724
Forfeited shares							0
Common shares issued under share incentive plans, net of forfeitures						0
Common shares issued to directors						23,127
Number at Mar. 31, 2020					119,945	10,305,404
Balance at Dec. 31, 2019		$ 442,403	$ 17,609	$ 270,768	$ (3,973)	$ 1		$ 0	$ 1
Class A common shares purchased, at cost							$ (143)
Other comprehensive income (loss):
Change in unrealized holding gains (losses)			(3,746)
Unrealized foreign currency translation gains	$ (1,303)		(1,303)
Other comprehensive loss, net of tax	(5,049)		(5,049)
Net income (loss)	(44,578)			(44,578)
Preferred share distributions	0			0
Dividends/ Distribution to shareholders				(3,641)
Share compensation plans		1,238
Balance at Mar. 31, 2020	674,636	443,641	12,560	222,549	$ (4,116)
Number at Dec. 31, 2020					0	10,263,722		4,000	4,133,366
Class A common shares purchased							9,815
Forfeited shares							178
Common shares issued under share incentive plans, net of forfeitures						20,104
Common shares issued to directors						20,006
Number at Mar. 31, 2021					9,993	10,303,832
Balance at Dec. 31, 2020	718,324	445,051	34,308	234,965	$ 0	$ 0		$ 4,000	$ 0
Class A common shares purchased, at cost							$ (283)
Other comprehensive income (loss):
Change in unrealized holding gains (losses)			(24,362)
Unrealized foreign currency translation gains	(93)		(93)
Other comprehensive loss, net of tax	(24,455)		(24,455)
Net income (loss)	5,517			5,517
Preferred share distributions	(110)			(110)
Dividends/ Distribution to shareholders				(3,684)
Share compensation plans		1,148
Balance at Mar. 31, 2021	$ 696,457	$ 446,199	$ 9,853	$ 236,688	$ (283)