Premises and Equipment (Summary of Premises and Equipment) (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2016	Dec. 31, 2014
Property, Plant and Equipment [Abstract]
Land	$ 12,899	$ 12,595
Buildings and improvements	94,686	90,778
Leasehold improvements	79,917	83,995
Fixtures and equipment	73,686	76,146
Data processing and software	195,308	220,002
Total premises and equipment	456,496	483,516
Less: Accumulated depreciation and amortization	(327,070)	(346,103)
Premises and equipment, net	129,426	137,413
Depreciation and amortization	$ 28,400	$ 30,800	$ 27,900