Other Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Other Expense
Business development and staff related	$ 7,449	$ 6,210	$ 6,642
Other loan expense	2,590	2,486	2,942
Director and shareholder expense	1,635	2,004	2,118
Armored carrier and courier expense	1,703	1,470	1,354
Property and sales tax	1,033	1,145	1,362
Other	9,310	8,016	7,031
Total other noninterest expense	$ 23,720	$ 21,331	$ 21,449