Parent Company Financial Statements (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Equity in net assets of subsidiaries [Abstract]
Other assets	$ 2,970	$ 3,228
Total assets	804,787	787,485
Liabilities [Abstract]
Subordinated debentures	20,619	20,619
Total liabilities	713,687	699,555
Stockholders' Equity	91,100	87,930	$ 86,456
Total liabilities and stockholders' equity	804,787	787,485
Statements of Operations [Abstract]
Interest income	32,224	30,750
Net interest income	24,594	22,189
Net income before income tax provision (benefit)	7,840	5,526
Income tax benefit	5,022	(10,014)
Net income	2,818	15,540
Cash flows from operating activities [Abstract]
Net income	2,818	15,540
Adjustments to reconcile net income to net cash from operating activities [Abstract]
Stock-based compensation	205	184
Deferred income taxes	4,794	(10,081)
Decrease in other assets	244	1,823
Net cash provided by operating activities	10,881	7,621
Cash flows from investing activities [Abstract]
Net cash (used in) provided by investing activities	(70,731)	3,276
Cash flows from financing activities [Abstract]
Preferred stock dividends	(280)	(7,840)
Repurchase of warrant	(520)	0
Stock redemption of Series B preferred stock	0	(23,393)
Proceeds from common stock issuance	207	10,584
Net cash provided by financing activities	14,689	12,526
(Decrease) increase in cash and cash equivalents	(45,161)	23,423
Cash and cash equivalents at beginning of period	67,014	43,591
Cash and cash equivalents at end of period	21,853	67,014
Severn Bancorp, Inc [Member]
ASSETS [Abstract]
Cash	1,310	2,012
Equity in net assets of subsidiaries [Abstract]
Bank	108,735	105,898
Nonbank	3,886	3,014
Other assets	1,421	1,265
Total assets	115,352	112,189
Liabilities [Abstract]
Subordinated debentures	20,619	20,619
Other liabilities	3,633	3,640
Total liabilities	24,252	24,259
Stockholders' Equity	91,100	87,930
Total liabilities and stockholders' equity	115,352	112,189
Statements of Operations [Abstract]
Interest income	0	0
Interest expense on subordinated debentures	824	973
Net interest income	(824)	(973)
General and administrative expenses	218	229
Net income before income tax provision (benefit)	(1,042)	(1,202)
Income tax benefit	(71)	(1,004)
Equity in undistributed net income of subsidiaries	3,789	15,738
Net income	2,818	15,540
Cash flows from operating activities [Abstract]
Net income	2,818	15,540
Adjustments to reconcile net income to net cash from operating activities [Abstract]
Equity in undistributed earnings of subsidiaries	(3,789)	(15,738)
Stock-based compensation	205	184
Deferred income taxes	(718)	(531)
Decrease in other assets	562	178
Decrease in accrued expenses and other liabilities	(7)	(1,965)
Net cash provided by operating activities	(929)	(2,332)
Cash flows from investing activities [Abstract]
Contributions from subsidiaries	820	24,000
Net cash (used in) provided by investing activities	820	24,000
Cash flows from financing activities [Abstract]
Preferred stock dividends	(280)	(7,840)
Repurchase of warrant	(520)	0
Stock redemption of Series B preferred stock	0	(23,393)
Proceeds from common stock issuance	207	10,584
Net cash provided by financing activities	(593)	(20,649)
(Decrease) increase in cash and cash equivalents	(702)	1,019
Cash and cash equivalents at beginning of period	2,012	993
Cash and cash equivalents at end of period	$ 1,310	$ 2,012