Contracts With Customers (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
Revenue from External Customer [Line Items]
Revenue from Contract with Customer, Including Assessed Tax									$ 57,453
RevenueOutsideScopeofTopic606									3,111
Noninterest Income	$ 15,952	$ 15,369	$ 15,119	$ 14,212	$ 15,367	$ 14,611	$ 14,921	$ 14,231	60,564	$ 63,607	$ 58,825
Fees and Commissions, Depositor Accounts [Domain]
Revenue from External Customer [Line Items]
Revenue from Contract with Customer, Including Assessed Tax									29,704
Fees and Commissions, Debit Cards [Domain]
Revenue from External Customer [Line Items]
Revenue from Contract with Customer, Including Assessed Tax									18,369
Fees and Commissions, Fiduciary and Trust Accounts [Domain]
Revenue from External Customer [Line Items]
Revenue from Contract with Customer, Including Assessed Tax									6,529
Other Non-Interest Income [Domain]
Revenue from External Customer [Line Items]
Revenue from Contract with Customer, Including Assessed Tax									$ 2,851