Changes in Accumulated Other Comprehensive Income by Component - Summary (Details) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2020	Mar. 31, 2019
Accumulated other comprehensive income
Beginning balance	$ 460,305	$ 440,780
Other comprehensive (loss) income before reclassifications	(542)	1,419
Losses (Gains) reclassified from other comprehensive income	9	(3)
Net current period other comprehensive (loss) income	(533)	1,416
Ending balance	438,179	442,549
Realized loss (less than $0.1 million for 2020)	100
Realized gain (less than $0.1 million for 2019)		100
Changes in other comprehensive (loss) income, tax expense (benefit)	(100)	400
Accumulated Other Comprehensive Income, net of taxes
Accumulated other comprehensive income
Beginning balance	2,919	158
Ending balance	$ 2,386	$ 1,574

Amount of realized gain on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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