Derivative Financial Instruments (Summary Amounts Included in Consolidated Statement of Income Related to Derivatives) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Interest rate swaps and caps | Trading Revenue
Derivative Instruments, Gain (Loss) [Line Items]
Income related to derivative instruments not designated in hedge relationships	$ (848)	$ 279
Mortgage banking derivatives | Mortgage Banking Revenue
Derivative Instruments, Gain (Loss) [Line Items]
Income related to derivative instruments not designated in hedge relationships	1,314	(9,537)
Covered call options | Fees From Covered Call Options
Derivative Instruments, Gain (Loss) [Line Items]
Income related to derivative instruments not designated in hedge relationships	4,402	11,470
Foreign exchange contracts | Trading Revenue
Derivative Instruments, Gain (Loss) [Line Items]
Income related to derivative instruments not designated in hedge relationships	$ (38)	$ (234)