Shareholders' Equity, Changes in Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	$ 305,383	$ 366,070	$ 364,316	$ 356,082
Other comprehensive income (loss) before reclassifications			(1,319)	15,349
Amounts reclassified from accumulated other comprehensive income (loss)			(157)	215
Net current-period other comprehensive income (loss)	20,072	6,801	(1,476)	15,564
Ending balance	336,038	367,416	336,038	367,416
Other Comprehensive Income (Loss) [Member]
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(12,179)	1,416	9,369	(7,347)
Ending balance	7,893	8,217	7,893	8,217
Foreign Currency [Member]
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance			(494)	(1,139)
Other comprehensive income (loss) before reclassifications			(466)	591
Amounts reclassified from accumulated other comprehensive income (loss)			0	0
Net current-period other comprehensive income (loss)			(466)	591
Ending balance	(960)	(548)	(960)	(548)
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			(853)	14,758
Amounts reclassified from accumulated other comprehensive income (loss)			(157)	215
Net current-period other comprehensive income (loss)			(1,010)	14,973
Ending balance	$ 8,853	$ 8,765	$ 8,853	$ 8,765

A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

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Amount after tax, before reclassification adjustments, of other comprehensive income (loss), attributable to parent.

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Amount after tax of other comprehensive income (loss) attributable to parent entity.

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Total of all stockholders' equity (deficit) items, net of receivables from officers, directors, owners, and affiliates of the entity which are attributable to the parent. The amount of the economic entity's stockholders' equity attributable to the parent excludes the amount of stockholders' equity which is allocable to that ownership interest in subsidiary equity which is not attributable to the parent (noncontrolling interest, minority interest). This excludes temporary equity and is sometimes called permanent equity.

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