Summary of Significant Accounting Policies (Narrative) (Details)	12 Months Ended
	Dec. 31, 2018 USD ($) item	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)	Jan. 01, 2019 USD ($)	Mar. 31, 2018 USD ($)
Property, Plant and Equipment [Line Items]
Gain Loss On Sales Of Loans Net		$ 294,000
Reclassification from AOCI to retained earnings	$ 19,000
Number of operation centers | item	2
Number of LPOs | item	5
Reclassification of OREO gains losses from noninterest income to noninterest expense		43,000,000	$ 436,000,000
Increase in assets as a result of business combinations					$ 1,600,000,000
Trading securities	$ 0	0	$ 0
Loans held for sale	$ 0	0
Number of mortgage loan sold | item	0
Equity securities	$ 4,428,000
Accumulated Other Comprehensive Income Loss, Reclassification Due To Accounting Standard Update Asu 2018 02	$ 19,000	196,000
Recognition Of Deferred Loss From Sale Of Oreo		$ 43,000
Maryland and Virginia
Property, Plant and Equipment [Line Items]
Number of branches | item	12
Waldrof
Property, Plant and Equipment [Line Items]
Number of branches | item	2
Leonardtown, La Plata
Property, Plant and Equipment [Line Items]
Number of branches | item	2
Scenario, Forecast [Member] | Accounting Standards Update 2016-02 [Member]
Property, Plant and Equipment [Line Items]
Right-of-Use Asset				$ 8,000,000
Lease liability				$ 11,000,000
Building and Building Improvements [Member] | Maximum [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, useful life	50 years
Building and Building Improvements [Member] | Minimum [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, useful life	10 years
Furniture and Fixtures [Member] | Maximum [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, useful life	15 years
Furniture and Fixtures [Member] | Minimum [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, useful life	3 years
Automobiles [Member] | Maximum [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, useful life	5 years
Automobiles [Member] | Minimum [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, useful life	4 years