Employee Benefit Plans (Narrative) (Details) - USD ($)	3 Months Ended												12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Defined Benefit Plan Disclosure [Line Items]
Employee Stock Ownership Plan (ESOP), cash contributions to ESOP													$ 229,000	$ 124,000	$ 242,000
Employee Stock Ownership Plan (ESOP), number of allocated shares (in shares)	156,451				161,173								156,451	161,173
Employee Stock Ownership Plan (ESOP), number of unallocated shares (in shares)	17,581				21,091								17,581	21,091
Employee Stock Ownership Plan (ESOP), allocated shares market value	$ 6,200,000				$ 5,300,000								$ 6,200,000	$ 5,300,000
Employee Stock Ownership Plan (ESOP), allocated excess of fair market value of leveraged ESOP shares released	$ (3,000)				$ 33,000								$ (3,000)	$ 33,000
Employee Stock Ownership Plan (ESOP), debt structure offset by cash		$ 63,000		$ 63,000
Earnings per share, basic (in dollars per share)	$ 0.73	$ 0.66	$ 0.65	$ 0.70	$ 0.69	$ 0.70	$ 0.42	$ 0.22	$ (0.10)	$ 0.60	$ 0.55	$ 0.51	$ 2.75	$ 2.02	$ 1.56
Employee Stock Ownership Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Share Price (in dollars per share)	$ 35.57				$ 29.24								$ 35.57	$ 29.24
Promissory notes	$ 602,000				$ 718,000								$ 602,000	$ 718,000
Employee Stock Ownership Plan (ESOP) promissory note amortization period													7 years
Employee Stock Ownership Plan (ESOP), Debt Structure, Direct Loan, Employer Cash Payments Used for Debt Service													$ 155,000	$ 174,000
Employee Stock Ownership Plan (ESOP), debt structure direct loan employer shares used for debt service (in shares)													4,815	6,061
Employee Stock Ownership Plan (ESOP), debt structure offset by purchase of common shares (in shares)													3,271	4,244
Employee Stock Ownership Plan (ESOP), debt structure offset by purchase of common shares, amount					137,000	$ 137,000							$ 39,000
Prime Rate [Member] | Employee Stock Ownership Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Employee Stock Ownership Plan (ESOP) basis spread on variable rate													1.00%
401 (K) Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Employer matching contribution (as a percent)													50.00%	50.00%	50.00%
Maximum employee contribution employer will match													8.00%	8.00%	8.00%
Minimim period of service													6 months
Period of service eligible for service													3 years
Retirement plan expense													$ 488,000	$ 405,000	$ 298,000
Nonqualified Retirement Plan For Non Employee Directors [Member]
Defined Benefit Plan Disclosure [Line Items]
Retirement plan expense													26,000	35,000	29,000
Liability	$ 2,200,000				$ 2,100,000								2,200,000	2,100,000
Maximum annual benefit following retirement													$ 3,500
Number of years following retirement benefit is paid													10 years
Employee benefit plan vesting period													2 years
Employee benefit plan requisite service period													15 years
Individual Supplemental Retirement Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Retirement plan expense													$ 885,000	$ 1,109,000	$ 637,000
Number of years following retirement benefit is paid													15 years
Maximum | Nonqualified Retirement Plan For Non Employee Directors [Member]
Defined Benefit Plan Disclosure [Line Items]
Period for distribution of deferred amount													10 years
Minimum | Nonqualified Retirement Plan For Non Employee Directors [Member]
Defined Benefit Plan Disclosure [Line Items]
Period for distribution of deferred amount													1 year