CONSOLIDATED STATEMENTS OF CHANGES IN STOCKHOLDERS' EQUITY - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-In Capital	Retained Earnings	Accumulated Other Comprehensive Income (Loss)
Balance at at Dec. 31, 2016	$ 533,572	$ 23,901	$ 165,871	$ 350,414	$ (6,614)
Net income	53,209	0	0	53,209	0
Other comprehensive income, net of tax	(243)	0	0	0	(243)
Common stock dividends - $1.04, $1.10 and $1.18 per share at December 31, 2017, 2018 and 2019 respectively	(25,134)	0	0	(25,134)	0
Stock compensation expense	2,164	0	2,164	0	0
Common stock issued pursuant to:
Stock option plan - 30,567, 20,888 and 15,080 shares at December 31, 2017, 2018 and 2019 respectively	593	31	562	0	0
Employee stock purchase plan - 17,578, 28,996 and 37,091 shares at December 31, 2017, 2018 and 2019 respectively	607	17	590	0	0
Restricted stock - 47,064, 38,360 and 54,789 shares at December 31, 2017, 2018 and 2019 respectively	(952)	47	(999)	0	0
Balance at at Dec. 31, 2017	563,816	23,996	168,188	378,489	(6,857)
Net income	100,864	0	0	100,864	0
Other comprehensive income, net of tax	(7,420)	0	0	0	(7,420)
Common stock dividends - $1.04, $1.10 and $1.18 per share at December 31, 2017, 2018 and 2019 respectively	(39,277)	0	0	39,277	0
Stock compensation expense	2,645	0	2,645	0	0
Common stock issued pursuant to:
Acquisition of WashingtonFirst Bankshares Inc. - 11,446,197 shares	446,640	11,446	435,194	0	0
Stock option plan - 30,567, 20,888 and 15,080 shares at December 31, 2017, 2018 and 2019 respectively	441	21	420	0	0
Employee stock purchase plan - 17,578, 28,996 and 37,091 shares at December 31, 2017, 2018 and 2019 respectively	954	29	925	0	0
Restricted stock - 47,064, 38,360 and 54,789 shares at December 31, 2017, 2018 and 2019 respectively	(760)	39	(799)	0	0
Reclassfication of tax effects from other comprehensive income	0	0	0	1,477	(1,477)
Balance at at Dec. 31, 2018	1,067,903	35,531	606,573	441,553	(15,754)
Net income	116,433	0	0	116,433	0
Other comprehensive income, net of tax	11,422	0	0	0	11,422
Common stock dividends - $1.04, $1.10 and $1.18 per share at December 31, 2017, 2018 and 2019 respectively	(42,272)	0	0	(42,272)	0
Stock compensation expense	3,042	0	3,042	0	0
Common stock issued pursuant to:
Stock option plan - 30,567, 20,888 and 15,080 shares at December 31, 2017, 2018 and 2019 respectively	334	15	319	0	0
Directors stock purchase plan - 867 shares at December 31, 2019	30	1	29	0	0
Employee stock purchase plan - 17,578, 28,996 and 37,091 shares at December 31, 2017, 2018 and 2019 respectively	1,069	37	1,032	0	0
Restricted stock - 47,064, 38,360 and 54,789 shares at December 31, 2017, 2018 and 2019 respectively	(703)	54	(757)	0	0
Purchase of treasury shares	(24,284)	(668)	(23,616)	0	0
Balance at at Dec. 31, 2019	$ 1,132,974	$ 34,970	$ 586,622	$ 515,714	$ (4,332)