Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Equity [Abstract]
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent	21.00%	21.00%	35.00%
Other Comprehensive Income (Loss), Net of Tax
Unrealized holding gains (losses) arising during the period. before tax	$ 78,744	$ (34,357)	$ 17,374
Unrealized holding gains (losses) arising during the period, tax effect	(5,535)	6,520	(5,379)
Unrealized holding gains (losses) arising during the period, net of tax	73,209	(27,837)	11,995
Reclassification adjustment for (gains) losses included in net income	(1,927)	(953)	546
Reclassification adjustment for (gains) losses included in net income, tax effect	405	200	(191)
Reclassification adjustment for (gains) losses included in net income, net of tax	(1,522)	(753)	355
Other Comprehensive Income (Loss), Transfers from Held-to-maturity to Available-for-Sale Securities, before Tax		3,588
Other Comprehensive Income (Loss), Transfers from Held-to-maturity to Available-for-Sale Securities, Tax		(218)
Other Comprehensive Income (Loss), Transfers from Held-to-maturity to Available-for-Sale Securities, Net of Tax		3,370
Effects on DAC and CCRA, before tax	81	130	292
Effects on DAC and CCRA, tax effect	(17)	(38)	(102)
Effects on DAC and CCRA, net of tax	64	92	190
Unrealized gains (losses) arising during period, net	76,898	(31,592)	18,212
Other Comprehensive Income (Loss), Tax, Portion Attributable to Parent	(5,147)	6,464	(5,672)
Other comprehensive income (loss)	$ 71,751	$ (25,128)	$ 12,540