Employee Benefits (Narrative) (Details) $ in Thousands	3 Months Ended			9 Months Ended		12 Months Ended
	Sep. 30, 2021 USD ($) employee	Dec. 31, 2020 USD ($)	Sep. 30, 2020 USD ($)	Sep. 30, 2021 USD ($) employee	Sep. 30, 2020 USD ($)	Dec. 31, 2020 USD ($)	Jan. 31, 2021 employee	Mar. 31, 2019 employee	Mar. 20, 2019 employee	Dec. 31, 2017 employee	Mar. 29, 2017 employee
Defined Benefit Plan Disclosure [Line Items]
BOLI added		$ 11,000		$ 7,200		$ 9,300
Cash surrender value of bank owned life insurance	$ 52,417	44,285		52,417		44,285
Earnings on bank-owned life insurance	326		$ 216	899	$ 577	577
Number of officers with split dollar life insurance arrangement | employee							15	1		11
Split dollar life insurance arrangement, death benefit	52,400			52,400
Split dollar life insurance arrangement, death benefit to be paid to insured's beneficiary	4,400			4,400
Split dollar life insurance arrangement, death benefit to be paid to Company	$ 48,000			$ 48,000
Number of officers with opportunity to retain benefit equal to two times highest base salary after separation | employee	4			4
Split dollar life insurance arrangement, accrued expense	$ 188	154		$ 188		154
Number of officers who entered into supplemental executive retirement agreement | employee									1		5
Defined contribution plan, accrued expense	3,400	$ 2,000		3,400		$ 2,000
Landmark Bancorp, Inc. [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined contribution plan, accrued expense	$ 1,000			$ 1,000