Other Noninterest Expenses (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Other Noninterest Expenses
Data processing service and maintenance contracts									$ 7,452	$ 6,687	$ 6,323
Professional fees									3,044	2,416	2,323
Marketing and advertising expenses									1,601	1,522	1,633
Telecommunication expenses									1,331	1,300	1,264
Travel and educational expenses									1,231	1,077	1,101
All other noninterest expenses									8,762	8,494	8,343
Total Other Noninterest Expenses	$ 17,758	$ 18,674	$ 18,761	$ 18,539	$ 18,080	$ 18,371	$ 18,403	$ 17,969	$ 23,421	$ 21,496	$ 20,987