Portfolio Loans Not Covered by Loss Share ("Non-covered") - Summary of Aging of Recorded Investment in Past Due Non-covered Loans by Portfolio Class and Category (Details) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2013	Dec. 31, 2012
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total	$ 2,078,568	$ 2,106,039
Non-Covered Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
30-89 Days Past Due	6,452	3,217
90 or More Days Past Due	11,322	8,278
Total Past Due	17,774	11,495
Current	2,060,794	2,094,544
Total	2,077,826	2,106,028
Total	2,078,568	2,106,039
Non-Covered Loans | Commercial & Industrial
Financing Receivable, Recorded Investment, Past Due [Line Items]
30-89 Days Past Due	597	14
90 or More Days Past Due	1,166	0
Total Past Due	1,763	14
Current	961,157	962,870
Total	962,920	962,884
Non-Covered Loans | Real Estate
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total	1,084,686	1,126,178
Non-Covered Loans | Real Estate | Commercial - Owner Occupied
Financing Receivable, Recorded Investment, Past Due [Line Items]
30-89 Days Past Due	1,016	1,352
90 or More Days Past Due	761	2,081
Total Past Due	1,777	3,433
Current	336,169	329,809
Total	337,946	333,242
Non-Covered Loans | Real Estate | Commercial - Investor Owned
Financing Receivable, Recorded Investment, Past Due [Line Items]
30-89 Days Past Due	2,961	0
90 or More Days Past Due	7,498	4,045
Total Past Due	10,459	4,045
Current	437,295	482,422
Total	447,754	486,467
Non-Covered Loans | Real Estate | Construction and Land Development
Financing Receivable, Recorded Investment, Past Due [Line Items]
30-89 Days Past Due	1,054	1,201
90 or More Days Past Due	1,258	1,559
Total Past Due	2,312	2,760
Current	145,576	158,151
Total	147,888	160,911
Non-Covered Loans | Real Estate | Residential
Financing Receivable, Recorded Investment, Past Due [Line Items]
30-89 Days Past Due	824	616
90 or More Days Past Due	639	593
Total Past Due	1,463	1,209
Current	149,635	144,349
Total	151,098	145,558
Non-Covered Loans | Consumer & Other
Financing Receivable, Recorded Investment, Past Due [Line Items]
30-89 Days Past Due	0	34
90 or More Days Past Due	0	0
Total Past Due	0	34
Current	30,962	16,943
Total	30,220	16,966
Total	$ 30,962	$ 16,977