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, 2015	$ 524,427	$ 24,296	$ 175,588	$ 325,840	$ (1,297)
Net income	48,250	0	0	48,250	0
Other comprehensive income, net of tax	(5,317)	0	0	0	(5,317)
Common stock dividends - $0.98, $1.04, and $1.10 per share at December 31, 2016, 2017 and 2018 respectively	(23,676)	0	0	(23,676)	0
Stock compensation expense	2,264	0	2,264	0	0
Common stock issued pursuant to:
Stock option plan - 44,067; 30,567 and 20,888 shares at December 31, 2016, 2017 and 2018 respectively	716	44	672	0	0
Director's stock purchase plan - 258 at December 31, 2016	7	0	7	0	0
Employee stock purchase plan - 23,779; 17,578 and 28,996 shares at December 31, 2016, 2017 and 2018 respectively	591	24	567	0	0
Restricted stock - 49,468; 47,064 and 38,360 shares at December 31, 2016, 2017 and 2018 respectively	(417)	49	(466)	0	0
Purchase of treasury shares - 512,459 at December 31, 2016	(13,273)	(512)	(12,761)	0	0
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 - $0.98, $1.04, and $1.10 per share at December 31, 2016, 2017 and 2018 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 - 44,067; 30,567 and 20,888 shares at December 31, 2016, 2017 and 2018 respectively	593	31	562	0	0
Employee stock purchase plan - 23,779; 17,578 and 28,996 shares at December 31, 2016, 2017 and 2018 respectively	607	17	590
Restricted stock - 49,468; 47,064 and 38,360 shares at December 31, 2016, 2017 and 2018 respectively	(952)	47	(999)
Balance at at Dec. 31, 2017	563,816	23,996	168,188	378,489	(6,857)
Net income	100,864			100,864
Other comprehensive income, net of tax	(7,420)				(7,420)
Common stock dividends - $0.98, $1.04, and $1.10 per share at December 31, 2016, 2017 and 2018 respectively	(39,277)			(39,277)
Stock compensation expense	2,645		2,645
Common stock issued pursuant to:
Acquisition of WashingtonFirst Bankshares Inc. - 11,446,197 shares	446,640	11,446	435,194
Stock option plan - 44,067; 30,567 and 20,888 shares at December 31, 2016, 2017 and 2018 respectively	441	21	420
Employee stock purchase plan - 23,779; 17,578 and 28,996 shares at December 31, 2016, 2017 and 2018 respectively	954	29	925
Restricted stock - 49,468; 47,064 and 38,360 shares at December 31, 2016, 2017 and 2018 respectively	(760)	39	(799)
Reclassfication of tax effects from other comprehensive income	0			1,477	(1,477)
Balance at at Dec. 31, 2018	$ 1,067,903	$ 35,531	$ 606,573	$ 441,553	$ (15,754)