Stockholders' Equity (Schedule of Changes in Accumulated Other Comprehensive Income (Loss) by Component) (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Estimated tax benefit (provision)
Beginning balance	$ 9	$ 1	$ 11
Other comprehensive income (loss) before reclassifications	(126)	174	(332)
Less: Amount reclassified from accumulated other comprehensive income (loss)	(95)	166	(322)
Net current period other comprehensive income (loss)	(31)	8	(10)
Ending balance	(22)	9	1
AOCI, after tax
Beginning balance	689,384	608,693	627,552
Other comprehensive income (loss) before reclassifications	542	(682)	1,249
Less: Amount reclassified from accumulated other comprehensive income (loss)	358	(626)	1,213
Net current period other comprehensive income (loss)	184	(56)	36
Ending balance	696,815	689,384	608,693
Unrealized gains (losses) on available-for-sale investments
AOCI, before tax
Beginning balance	(2)	(2)	(18)
Other comprehensive income (loss) before reclassifications	0	0	16
Less: Amount reclassified from accumulated other comprehensive income (loss)	0	0	0
Net current period other comprehensive income (loss)	0	0	16
Ending balance	(2)	(2)	(2)
Unrealized gains (losses) on derivatives
AOCI, before tax
Beginning balance	(42)	22	(8)
Other comprehensive income (loss) before reclassifications	668	(856)	1,565
Less: Amount reclassified from accumulated other comprehensive income (loss)	453	(792)	1,535
Net current period other comprehensive income (loss)	215	(64)	30
Ending balance	173	(42)	22
AOCI
AOCI, after tax
Beginning balance	(35)	21	(15)
Ending balance	$ 149	$ (35)	$ 21

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