Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Equity [Abstract]
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent	21.00%	35.00%	35.00%
Other Comprehensive Income (Loss), Net of Tax
Unrealized holding gains (losses) arising during the period. before tax	$ (34,357)	$ 17,374	$ (1,608)
Unrealized holding gains (losses) arising during the period, tax effect	6,520	(5,379)	563
Unrealized holding gains (losses) arising during the period, net of tax	(27,837)	11,995	(1,045)
Reclassification adjustment for (gains) losses included in net income	(953)	546	1,974
Reclassification adjustment for (gains) losses included in net income, tax effect	200	(191)	(691)
Reclassification adjustment for (gains) losses included in net income, net of tax	(753)	355	1,283
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	130	292	(51)
Effects on DAC and CCRA, tax effect	(38)	(102)	18
Effects on DAC and CCRA, net of tax	92	190	(33)
Other comprehensive income (loss), before tax	(31,592)	18,212	315
Other comprehensive income (loss), tax effect	6,464	(5,672)	(110)
Other comprehensive income (loss)	$ (25,128)	$ 12,540	$ 205