Reclassification of Accumulated Other Comprehensive Income (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Dec. 31, 2020	Dec. 31, 2019
Supplemental Comprehensive Income Disclosures [Abstract]
Unrealized holding gains on securities arising during the period	$ (15,804)	$ 19,503
Reclassification adjustment for gains on securities included in net income	(6)	(19)
Total unrealized gains on securities	(15,810)	19,484
Unrealized holding gains (losses) on derivatives arising during the period	1,842	(4,581)
Unrealized holding gains on securities arising during the period	3,319	(4,096)
Reclassification adjustment for gains on derivatives included in net income, before Tax	0	0
Total unrealized gain on derivatives	1,842	(4,581)
Reclassification adjustment for gains on securities included in net income	1	4
Total other comprehensive (loss) income	(13,968)	14,903
Other Comprehensive Income (Loss), Securities, Available-for-sale, Tax	3,320	(4,092)
Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, Tax	(387)	962
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI on Derivatives, Tax	0	0
Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, Tax, Total	(387)	962
Other Comprehensive Income (Loss), Tax	2,933	(3,130)
Other comprehensive income (loss) before reclassification adjustment	(12,485)	15,407
Total unrealized (losses) gains on securities	(12,490)	15,392
Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, Net of Tax	1,455	(3,619)
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI on Derivatives, Net of Tax	0	0
Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, Net of Tax, Total	1,455	(3,619)
Total other comprehensive (loss) income	(11,035)	11,773
Reclassification adjustment for gains on securities included in net income	5	15
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated Other Comprehensive Income (Loss), Net of Tax	6,198		$ 17,233
Other comprehensive income (loss) before reclassification adjustment	(12,485)	15,407
Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, Net of Tax	1,455	(3,619)
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI on Derivatives, Net of Tax	0	0
Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, before Tax	1,842	(4,581)
Other comprehensive income (loss)	(11,035)	11,773
Accumulated Net Unrealized Investment Gain (Loss) [Member]
Supplemental Comprehensive Income Disclosures [Abstract]
Other comprehensive income (loss) before reclassification adjustment	(12,485)	15,407
Total other comprehensive (loss) income	(12,490)	15,392
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated Other Comprehensive Income (Loss), Net of Tax	7,820	19,972	20,310	$ 4,580
Other comprehensive income (loss) before reclassification adjustment	(12,485)	15,407
Amounts reclassified from accumulated other comprehensive income (loss)	(5)	(15)
Other comprehensive income (loss)	(12,490)	15,392
Accumulated Defined Benefit Plans Adjustment [Member]
Supplemental Comprehensive Income Disclosures [Abstract]
Other comprehensive income (loss) before reclassification adjustment	0	0
Total other comprehensive (loss) income	0	0
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated Other Comprehensive Income (Loss), Net of Tax	(182)	365	(182)	365
Other comprehensive income (loss) before reclassification adjustment	0	0
Amounts reclassified from accumulated other comprehensive income (loss)	0	0
Other comprehensive income (loss)	0	0
Derivative [Member]
Supplemental Comprehensive Income Disclosures [Abstract]
Total other comprehensive (loss) income	1,455	(3,619)
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated Other Comprehensive Income (Loss), Net of Tax	(1,440)	(2,985)	(2,895)	634
Other comprehensive income (loss)	1,455	(3,619)
Accumulated Other Comprehensive Income (Loss), net [Member]
Supplemental Comprehensive Income Disclosures [Abstract]
Total other comprehensive (loss) income	(11,035)	11,773
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated Other Comprehensive Income (Loss), Net of Tax	6,198	17,352	$ 17,233	$ 5,579
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax	(11,030)	11,788
Amounts reclassified from accumulated other comprehensive income (loss)	(5)	(15)
Other comprehensive income (loss)	$ (11,035)	$ 11,773