Consolidated Statements of Changes in Stockholders' Equity (Unaudited) - USD ($) $ in Thousands	Total	Common Stock	Retained Earnings	Accumulated Other Comprehensive Income (Loss)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cumulative adjustment for adoption of ASU 2016-01				$ (2,043)
January 1, 2018, as adjusted				(4,392)
Balance at beginning of period at Dec. 31, 2017	$ 583,122	$ 512,734	$ 72,737	(2,349)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	15,255		15,255
Other comprehensive loss, net of tax	(5,449)			(5,449)
Stock based compensation	994	994
Exercise of stock options	248	248
Retirement of restricted stock	(744)	(744)
Cash dividends, common stock	(4,778)		(4,778)
Balance at end of period at Mar. 31, 2018	588,648	513,232	85,257	(9,841)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cumulative adjustment for adoption of ASU 2016-01				0
January 1, 2018, as adjusted				(7,838)
Balance at beginning of period at Dec. 31, 2018	623,739	514,703	116,874	(7,838)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	15,626
Other comprehensive loss, net of tax	4,149			4,149
Stock based compensation	696	696
Retirement of restricted stock	(571)	(571)
Cash dividends, common stock	(5,838)		(5,838)
Issuance of stock for Highlands acquisition	43,417	43,417
Balance at end of period at Mar. 31, 2019	$ 681,343	$ 558,245	$ 126,787	$ (3,689)