Premises and Equipment - Narrative (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Property, Plant and Equipment [Abstract]
Depreciation expense	$ 14,200	$ 12,000	$ 11,500
Rent expense	$ 4,700	$ 4,320	$ 4,130