Business Combinations (Schedule of Fair Value of Net Assets Acquired Acquired and Liabilities Assumed - Capital One) (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018	Dec. 31, 2017
Business Acquisition [Line Items]
Goodwill	$ 792,084	$ 790,972	$ 745,523
Capital One [Member]
Business Acquisition [Line Items]
Accounts receivable	2,803
Identifiable intangible assets	27,562
Total identifiable assets	30,365
Deposit liabilities	217,432
Other liabilities	151
Total liabilities	217,583
Net identifiable assets acquired (liabilities assumed)	(187,218)
Consideration received	140,657
Goodwill	$ 46,561