Loans and the Allowance for Loan Losses (Details 9) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2014		Dec. 31, 2013
Fair value of loans determined to be impaired and not to be impaired at the time of acquisition
Loans acquired with deteriorated credit quality	$ 375,055		$ 448,930
Impaired Covered Loans
Fair value of loans determined to be impaired and not to be impaired at the time of acquisition
Loans acquired with deteriorated credit quality	13,240		24,519
Other Covered Loans
Fair value of loans determined to be impaired and not to be impaired at the time of acquisition
Loans acquired with deteriorated credit quality	142,079		157,155
Not Covered Loans
Fair value of loans determined to be impaired and not to be impaired at the time of acquisition
Loans acquired with deteriorated credit quality	219,736		267,256
Contractually-required principal and interest
Fair value of loans determined to be impaired and not to be impaired at the time of acquisition
Loans acquired with deteriorated credit quality	485,291
Contractually-required principal and interest | Impaired Covered Loans
Fair value of loans determined to be impaired and not to be impaired at the time of acquisition
Loans acquired with deteriorated credit quality	52,678
Contractually-required principal and interest | Other Covered Loans
Fair value of loans determined to be impaired and not to be impaired at the time of acquisition
Loans acquired with deteriorated credit quality	176,021
Contractually-required principal and interest | Not Covered Loans
Fair value of loans determined to be impaired and not to be impaired at the time of acquisition
Loans acquired with deteriorated credit quality	256,592
Nonaccretable Difference
Fair value of loans determined to be impaired and not to be impaired at the time of acquisition
Loans acquired with deteriorated credit quality	(102,613)	[1]
Nonaccretable Difference | Impaired Covered Loans
Fair value of loans determined to be impaired and not to be impaired at the time of acquisition
Loans acquired with deteriorated credit quality	(39,437)	[1]
Nonaccretable Difference | Other Covered Loans
Fair value of loans determined to be impaired and not to be impaired at the time of acquisition
Loans acquired with deteriorated credit quality	(30,500)	[1]
Nonaccretable Difference | Not Covered Loans
Fair value of loans determined to be impaired and not to be impaired at the time of acquisition
Loans acquired with deteriorated credit quality	(32,676)	[1]
Cash flows expected to be collected
Fair value of loans determined to be impaired and not to be impaired at the time of acquisition
Loans acquired with deteriorated credit quality	382,678
Cash flows expected to be collected | Impaired Covered Loans
Fair value of loans determined to be impaired and not to be impaired at the time of acquisition
Loans acquired with deteriorated credit quality	13,241
Cash flows expected to be collected | Other Covered Loans
Fair value of loans determined to be impaired and not to be impaired at the time of acquisition
Loans acquired with deteriorated credit quality	145,521
Cash flows expected to be collected | Not Covered Loans
Fair value of loans determined to be impaired and not to be impaired at the time of acquisition
Loans acquired with deteriorated credit quality	223,916
Accretable Yield
Fair value of loans determined to be impaired and not to be impaired at the time of acquisition
Loans acquired with deteriorated credit quality	(7,623)	[2]
Accretable Yield | Impaired Covered Loans
Fair value of loans determined to be impaired and not to be impaired at the time of acquisition
Loans acquired with deteriorated credit quality	(1)	[2]
Accretable Yield | Other Covered Loans
Fair value of loans determined to be impaired and not to be impaired at the time of acquisition
Loans acquired with deteriorated credit quality	(3,442)	[2]
Accretable Yield | Not Covered Loans
Fair value of loans determined to be impaired and not to be impaired at the time of acquisition
Loans acquired with deteriorated credit quality	$ (4,180)	[2]

[1] Represents contractual principal and interest cash flows of $93,738 and $8,875, respectively, not expected to be collected.

[2] Represents contractual interest payments of $5,182 expected to be collected and purchase discount of $3,336.