Employee Benefits (Narrative) (Details) $ in Thousands	1 Months Ended	3 Months Ended		9 Months Ended
	Mar. 31, 2017 USD ($)	Sep. 30, 2018 USD ($) employee	Sep. 30, 2017 USD ($)	Sep. 30, 2018 USD ($) employee	Sep. 30, 2017 USD ($)	Dec. 31, 2017 USD ($) employee	Mar. 29, 2017 employee
Employee Benefits [Abstract]
Purchase of life insurance policies	$ 8,000				$ 8,000
Cash surrender value of bank owned life insurance		$ 20,464		$ 20,464		$ 20,017
Earnings on bank-owned life insurance		150	$ 158	448	$ 422
Number of officers with split dollar life insurance arrangement | employee						11
Split dollar life insurance arrangement, death benefit		20,500		20,500
Split dollar life insurance arrangement, death benefit to be paid to insured's beneficiary		4,100		4,100
Split dollar life insurance arrangement, death benefit to be paid to Company		$ 16,400		$ 16,400
Number of officers with opportunity to retain benefit equal to two times highest base salary after separation | employee		3		3
Split dollar life insurance arrangement, accrued expense		$ 55		$ 55
Number of officers who entered into supplemental executive retirement agreement | employee							5
Defined contribution plan, accrued expense		$ 743		$ 743