Allowance for Loan Losses Allowance for Losses on Lending-Related Commitments and Impaired Loans (Summary of Activity in the Allowance for Covered Loan Losses) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013
Allowance for Covered Loan Losses [Roll Forward]
Balance at beginning of period	$ 10,092	$ 13,454
Provision for covered loan losses before benefit attributable to FDIC loss share agreements	(11,762)	246
Benefit attributable to FDIC loss share agreements	9,410	(197)
Net provision for covered loan losses	(2,352)	49
(Decrease) increase in FDIC indemnification asset	(9,410)	197
Loans charged-off	(5,521)	(15,085)
Recoveries of loans charged-off	9,322	11,477
Net recoveries (charge-offs)	3,801	(3,608)
Balance at end of period	$ 2,131	$ 10,092