Acquisitions - Narrative (Details) - BNC Bancorp $ in Thousands	Jun. 16, 2017 USD ($)
Business Acquisition [Line Items]
Transaction costs	$ 7,200
Fair value of net assets assumed including estimated identifiable intangible assets	602,689
Fair Value Adjustments
Business Acquisition [Line Items]
Fair value of net assets assumed including estimated identifiable intangible assets	$ (82,026)	[1]

[1] The amount represents the adjustment of the book value of BNC's assets and liabilities to their estimated fair value on the date of acquisition. Fair value adjustments were updated subsequent to the merger date based on the results of finalized valuation assessments.