Parent Corporation Only Financial Statements (Details) - Condensed Statements of Income - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income:
Dividend income from subsidiaries									$ 1,421	$ 1,410	$ 1,081
Net Income	$ 10,580	$ 13,077	$ 7,683	$ 11,880	$ (2,024)	$ 11,856	$ 10,859	$ 10,391	43,220	31,082	41,311
Parent Company [Member]
Income:
Dividend income from subsidiaries									13,000	12,400	10,537
Other income									13	8	7
Total Income									13,013	12,408	10,544
Expenses									(3,251)	(3,252)	(1,705)
Income before equity in undistributed earnings of subsidiaries									9,762	9,156	8,839
Equity in undistributed earnings of subsidiaries									33,458	21,926	32,472
Net Income									$ 43,220	$ 31,082	$ 41,311