Premises and Equipment - Summary of Premises and Equipment (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Premises and Equipment [Line Items]
Total Cost	$ 233,626	$ 228,827
Accumulated Depreciation and Amortization	(140,206)	(132,975)
Net	93,420	95,852
Land
Premises and Equipment [Line Items]
Total Cost	21,762	22,042
Buildings and Leasehold Improvements
Premises and Equipment [Line Items]
Total Cost	125,366	124,441
Equipment
Premises and Equipment [Line Items]
Total Cost	$ 86,498	$ 82,344