Parent Company Financial Information - Consolidated Statements of Cash Flows (Details) - USD ($) $ in Thousands		12 Months Ended
	Sep. 30, 2011	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Cash Flows from Operating Activities:
Net income		$ 16,301	$ 15,039	$ 12,741
Adjustments to reconcile net income to net cash provided by operating activities:
Net change in other assets		(1,390)	1,778	(2,057)
Net change in other liabilities		867	(118)	524
Net cash provided by operating activities		16,117	19,262	16,598
Cash Flows from Investing Activities:
Purchases of securities available for sale		(168,069)	(120,040)	(89,151)
Cash paid in bank acquisition		0	(5,935)	0
Net cash used in investing activities		(175,366)	(17,364)	(40,799)
Cash Flows from Financing Activities:
Common stock dividends paid		(8,266)	(8,068)	(7,237)
Repurchase of common stock		(1,292)	(3,506)	(1,508)
Proceeds from exercise of stock options		142	789	442
Proceeds from issuance of common stock	$ 619
Net cash provided by financing activities		117,119	26,136	23,823
Net Increase (Decrease) in Cash and Cash Equivalents		(42,130)	28,034	(378)
Cash and Cash Equivalents at Beginning of Period		95,337	67,303	67,681
Cash and Cash Equivalents at End of Period		53,207	95,337	67,303
Parent Company
Cash Flows from Operating Activities:
Net income		16,301	15,039	12,741
Adjustments to reconcile net income to net cash provided by operating activities:
Equity in (undistributed) distributions of subsidiary		(1,320)	(4,749)	3,585
Net change in other assets		(57)	257	(17)
Net change in other liabilities		163	106	102
Net cash provided by operating activities		15,087	10,653	16,411
Cash Flows from Investing Activities:
Purchases of securities available for sale		(6,588)	0	0
Investment in banking subsidiary		0	563	0
Cash paid in bank acquisition		0	(5,935)	0
Net cash used in investing activities		(6,588)	(5,372)	0
Cash Flows from Financing Activities:
Common stock dividends paid		(8,266)	(8,068)	(7,237)
Repurchase of common stock		(1,292)	(3,506)	(1,508)
Proceeds from exercise of stock options		142	789	442
Proceeds from issuance of common stock		0	95	0
Net cash provided by financing activities		(9,416)	(10,690)	(8,303)
Net Increase (Decrease) in Cash and Cash Equivalents		(917)	(5,409)	8,108
Cash and Cash Equivalents at Beginning of Period		5,571	10,980	2,872
Cash and Cash Equivalents at End of Period		$ 4,654	$ 5,571	$ 10,980