Summary Of Significant Accounting Policies (Narrative) (Details)			1 Months Ended	12 Months Ended
		Oct. 27, 2016	May 31, 2016 USD ($) $ / shares shares	Dec. 31, 2018 USD ($) segment shares	Dec. 31, 2017 shares	Dec. 31, 2016 USD ($) shares	Jan. 01, 2019 USD ($)
Summary Of Significant Accounting Policies [Line Items]
Stock split ratio		1.5
Stock split				3-for-2
Stock dividend rate, percentage		50.00%
Common stock issued in public offering, net of issuance costs (in shares) | shares			1,300,000
Shares issued, price per share | $ / shares			$ 29.00
Common stock issued in public offering, net of issuance costs			$ 35,270,000			$ 35,270,000
Number of reportable segments | segment				1
Post Split [Member]
Summary Of Significant Accounting Policies [Line Items]
Post-split (in shares) | shares			1,950,000
Shares issued, price per share | $ / shares			$ 19.33
RSUs [Member]
Summary Of Significant Accounting Policies [Line Items]
Anti-dilutive securities | shares				6,122	0	0
Employee Stock Option [Member]
Summary Of Significant Accounting Policies [Line Items]
Anti-dilutive securities | shares					0	0
Award vesting period				5 years
Building [Member] | Minimum [Member]
Summary Of Significant Accounting Policies [Line Items]
Estimated useful lives				31 years
Building [Member] | Maximum [Member]
Summary Of Significant Accounting Policies [Line Items]
Estimated useful lives				40 years
Leasehold Improvements [Member] | Minimum [Member]
Summary Of Significant Accounting Policies [Line Items]
Estimated useful lives				5 years
Leasehold Improvements [Member] | Maximum [Member]
Summary Of Significant Accounting Policies [Line Items]
Estimated useful lives				20 years
Furniture, Fixtures and Equipment [Member] | Minimum [Member]
Summary Of Significant Accounting Policies [Line Items]
Estimated useful lives				3 years
Furniture, Fixtures and Equipment [Member] | Maximum [Member]
Summary Of Significant Accounting Policies [Line Items]
Estimated useful lives				10 years
Accumulated Other Comprehensive Income (Loss) [Member]
Summary Of Significant Accounting Policies [Line Items]
Reclassification of stranded tax effects upon the adoption of ASU 2018-02	[1]			$ (277,000)
Accumulated Other Comprehensive Income (Loss) [Member] | Accounting Standards Update 2018-02 [Member]
Summary Of Significant Accounting Policies [Line Items]
Reclassification of stranded tax effects upon the adoption of ASU 2018-02				$ 277,000
Subsequent Event [Member] | Accounting Standards Update 2018-02 [Member]
Summary Of Significant Accounting Policies [Line Items]
Operating Lease, Right-of-Use Asset							$ 15,000,000
Operating Lease, Right-of-Use Asset, Statement of Financial Position [Extensible List]							us-gaap:Assets
Operating Lease, Liability							$ 15,000,000
Operating Lease, Liability, Statement of Financial Position [Extensible List]							us-gaap:Liabilities

[1] The adoption of Accounting Standards Update ("ASU") 2018-02 "Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income" in the first quarter of 2018 allowed the Corporation to reclassify certain stranded tax effects arising from the enactment of the Tax Cuts and Jobs Act ("Tax Act") in December 2017 from accumulated other comprehensive income to retained earnings. See "Adoption of New Accounting Standards" for more information regarding the effects of adopting ASU 2018-02.