Shareholders' Equity, Changes in Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	$ 336,038	$ 367,416	$ 364,316	$ 356,082
Other comprehensive income (loss) before reclassifications			4,371	16,990
Amounts reclassified from accumulated other comprehensive income (loss)			445	(49)
Other comprehensive income	6,292	1,377	4,816	16,941
Ending balance	344,664	363,430	344,664	363,430
Other Comprehensive Income (Loss) [Member]
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	7,893	8,217	9,369	(7,347)
Ending balance	14,185	9,594	14,185	9,594
Foreign Currency [Member]
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance			(494)	(1,139)
Other comprehensive income (loss) before reclassifications			(307)	402
Amounts reclassified from accumulated other comprehensive income (loss)			0	0
Other comprehensive income			(307)	402
Ending balance	(801)	(737)	(801)	(737)
Unrealized Holding Gains (Losses) on Available-for-sale Securities [Member]
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance			9,863	(6,208)
Other comprehensive income (loss) before reclassifications			4,678	16,588
Amounts reclassified from accumulated other comprehensive income (loss)			445	(49)
Other comprehensive income			5,123	16,539
Ending balance	$ 14,986	$ 10,331	$ 14,986	$ 10,331