Consolidated Statements of Changes in Stockholders' Equity (Unaudited) - USD ($) $ in Thousands	Total	Cumulative adjustment for adoption of ASU 842	January 1, 2019, as adjusted	Common Stock	Common Stock January 1, 2019, as adjusted	Retained Earnings	Retained Earnings Cumulative adjustment for adoption of ASU 842	Retained Earnings January 1, 2019, as adjusted	Treasury Stock	Treasury Stock January 1, 2019, as adjusted	AOCI Attributable to Parent [Member]	AOCI Attributable to Parent [Member] January 1, 2019, as adjusted
Balance at beginning of period at Dec. 31, 2018	$ 623,739	$ 125	$ 623,864	$ 514,703	$ 514,703	$ 116,874	$ 125	$ 116,999	$ 0	$ 0	$ (7,838)	$ (7,838)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	33,083					33,083
Other comprehensive income, net of tax	9,646										9,646
Stock based compensation	1,264			1,264
Issuance of stock for Highlands acquisition	43,417			43,417
Retirement of restricted stock	(616)			(616)
Cash dividends on common stock	(12,195)					(12,195)
Balance at end of period at Jun. 30, 2019	$ 698,463			558,768		137,887			0		1,808
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common stock, dividends price per share (in usd per share)	$ 0.24
Balance at beginning of period at Mar. 31, 2019	$ 681,343			558,245		126,787			0		(3,689)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	17,457					17,457
Other comprehensive income, net of tax	5,497										5,497
Stock based compensation	568			568
Retirement of restricted stock	(45)			(45)
Cash dividends on common stock	(6,357)					(6,357)
Balance at end of period at Jun. 30, 2019	$ 698,463			558,768		137,887			0		1,808
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common stock, dividends price per share (in usd per share)	$ 0.125
Balance at beginning of period at Dec. 31, 2019	$ 725,263			560,263		162,752			0		2,248
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	24,243					24,243
Other comprehensive income, net of tax	9,169										9,169
Purchase of treasury stock, 131,035 shares	(1,452)								(1,452)
Stock based compensation	1,461			1,461
Retirement of restricted stock	(467)			(467)
Cash dividends on common stock	(12,728)					(12,728)
Balance at end of period at Jun. 30, 2020	$ 745,489			561,257		174,267			(1,452)		11,417
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common stock, dividends price per share (in usd per share)	$ 0.25
Balance at beginning of period at Mar. 31, 2020	$ 736,922			560,653		168,780			(1,452)		8,941
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	11,851					11,851
Other comprehensive income, net of tax	2,476										2,476
Stock based compensation	614			614
Retirement of restricted stock	(10)			(10)
Cash dividends on common stock	(6,364)					(6,364)
Balance at end of period at Jun. 30, 2020	$ 745,489			$ 561,257		$ 174,267			$ (1,452)		$ 11,417
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common stock, dividends price per share (in usd per share)	$ 0.125