Changes in Accumulated Other Comprehensive Income by Component - Summary (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Accumulated other comprehensive income
Beginning balance	$ 438,179	$ 442,549	$ 460,305	$ 440,780
Other comprehensive income before reclassifications			1,057	2,286
Losses (Gains) reclassified from other comprehensive income			66	(79)
Net current period other comprehensive (loss) income			1,123	2,207
Ending balance	449,687	449,648	449,687	449,648
Realized loss			100
Realized gain			100
Changes in other comprehensive (loss) income, tax expense (benefit)			300	600
Accumulated Other Comprehensive Income, net of taxes
Accumulated other comprehensive income
Beginning balance	2,386	1,574	2,919	158
Ending balance	$ 4,042	$ 2,365	$ 4,042	$ 2,365

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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