CONDENSED CONSOLIDATED STATEMENTS OF CHANGES IN STOCKHOLDERS' EQUITY - UNAUDITED - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-In Capital	Retained Earnings	Accumulated Other Comprehensive Income (Loss)
Balance at at Dec. 31, 2017	$ 563,816	$ 23,996	$ 168,188	$ 378,489	$ (6,857)
Net income	75,298	0	0	75,298	0
Other comprehensive income, net of tax	(16,086)	0	0	0	(16,086)
Common stock dividends - $0.30 and $0.28 per share for the quarter; $0.88 and $0.82 per share for year to date September 30, 2019 and 2018 respectively	(29,273)	0	0	(29,273)	0
Stock compensation expense	1,941	0	1,941	0	0
Common stock issued pursuant to:
Acquisition of WashingtonFirst - 11,446,197 shares	446,640	11,446	435,194	0	0
Stock option plan 1,325; 1,991 shares for the quarter, and 12,222; 19,918 shares year to date September 30, 2019 and 2018 respectively	423	20	403	0	0
Employee stock purchase plan - 9,544; 7,607 shares for the quarter and 27,210; 21,428 shares for year to date September 30 2019 and 2018 respectively	717	22	695	0	0
Restricted stock 54,789; 37,705 shares for year to date September 30 2019 and 2018 respectively	(760)	38	(798)	0	0
Reclassfication of tax effects from other comprehensive income	0	0	0	1,477	(1,477)
Balance at at Sep. 30, 2018	1,042,716	35,522	605,623	425,991	(24,420)
Balance at at Jun. 30, 2018	1,026,349	35,512	604,631	406,762	(20,556)
Net income	29,234	0	0	29,234	0
Other comprehensive income, net of tax	(3,864)	0	0	0	(3,864)
Common stock dividends - $0.30 and $0.28 per share for the quarter; $0.88 and $0.82 per share for year to date September 30, 2019 and 2018 respectively	(10,005)	0	0	(10,005)	0
Stock compensation expense	691	0	691	0	0
Common stock issued pursuant to:
Stock option plan 1,325; 1,991 shares for the quarter, and 12,222; 19,918 shares year to date September 30, 2019 and 2018 respectively	53	2	51	0	0
Employee stock purchase plan - 9,544; 7,607 shares for the quarter and 27,210; 21,428 shares for year to date September 30 2019 and 2018 respectively	258	8	250	0	0
Balance at at Sep. 30, 2018	1,042,716	35,522	605,623	425,991	(24,420)
Balance at at Dec. 31, 2018	1,067,903	35,531	606,573	441,553	(15,754)
Net income	87,976	0	0	87,976	0
Other comprehensive income, net of tax	13,046	0	0	0	13,046
Common stock dividends - $0.30 and $0.28 per share for the quarter; $0.88 and $0.82 per share for year to date September 30, 2019 and 2018 respectively	(31,509)	0	0	(31,509)	0
Stock compensation expense	2,259	0	2,259	0	0
Common stock issued pursuant to:
Director's stock purchase plan - 867 shares for year to date September 30 2019	30	1	29	0	0
Stock option plan 1,325; 1,991 shares for the quarter, and 12,222; 19,918 shares year to date September 30, 2019 and 2018 respectively	259	12	247	0	0
Employee stock purchase plan - 9,544; 7,607 shares for the quarter and 27,210; 21,428 shares for year to date September 30 2019 and 2018 respectively	779	27	752	0	0
Restricted stock 54,789; 37,705 shares for year to date September 30 2019 and 2018 respectively	(702)	55	(757)	0	0
Balance at at Sep. 30, 2019	1,140,041	35,626	609,103	498,020	(2,708)
Balance at at Jun. 30, 2019	1,119,445	35,615	608,006	479,389	(3,565)
Net income	29,383	0	0	29,383	0
Other comprehensive income, net of tax	857	0	0	0	857
Common stock dividends - $0.30 and $0.28 per share for the quarter; $0.88 and $0.82 per share for year to date September 30, 2019 and 2018 respectively	(10,752)	0	0	(10,752)	0
Stock compensation expense	786	0	786	0	0
Common stock issued pursuant to:
Stock option plan 1,325; 1,991 shares for the quarter, and 12,222; 19,918 shares year to date September 30, 2019 and 2018 respectively	35	1	34	0	0
Employee stock purchase plan - 9,544; 7,607 shares for the quarter and 27,210; 21,428 shares for year to date September 30 2019 and 2018 respectively	287	10	277	0	0
Balance at at Sep. 30, 2019	$ 1,140,041	$ 35,626	$ 609,103	$ 498,020	$ (2,708)