Acquisitions and Divestitures (Merger and Integration Expenses) (Details) - Capital Bank Financial Corp $ in Thousands	3 Months Ended
	Mar. 31, 2018 USD ($)
Business Acquisition [Line Items]
Merger and integration expense	$ 30,060
Professional fees
Business Acquisition [Line Items]
Merger and integration expense	5,632
Employee compensation, incentives and benefits
Business Acquisition [Line Items]
Merger and integration expense	3,946
Contract employment and outsourcing
Business Acquisition [Line Items]
Merger and integration expense	1,399
Miscellaneous expense
Business Acquisition [Line Items]
Merger and integration expense	2,042
All other expense
Business Acquisition [Line Items]
Merger and integration expense	$ 17,041