Goodwill and Other Intangible Assets (Aggregate Amortization Expense) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Finite-Lived Intangible Assets [Line Items]
Aggregate amortization expense	$ 22,050	$ 22,417	$ 19,781
Core Deposit Intangibles [Member]
Finite-Lived Intangible Assets [Line Items]
Aggregate amortization expense	18,566	19,442	16,411
Customer Relationships [Member]
Finite-Lived Intangible Assets [Line Items]
Aggregate amortization expense	2,682	1,975	2,172
Merchant Processing Relationships [Member]
Finite-Lived Intangible Assets [Line Items]
Aggregate amortization expense	$ 802	$ 1,000	$ 1,198