Portfolio Loans Not Covered by Loss Share ("Non-covered") - Summary of Non-covered Loans Individually Evaluated for Impairment by Category (Details) (Non-Covered Loans, USD $) In Thousands, unless otherwise specified	3 Months Ended	12 Months Ended
	Mar. 31, 2013	Dec. 31, 2012
Financing Receivable, Impaired [Line Items]
Unpaid Contractual Principal Balance	$ 36,003	$ 45,218
Recorded Investment With No Allowance	11,850	5,645
Recorded Investment With Allowance	18,529	33,082
Total Recorded Investment	30,379	38,727
Related Allowance	6,040	8,176
Average Recorded Investment	34,126	39,491
Commercial & Industrial
Financing Receivable, Impaired [Line Items]
Unpaid Contractual Principal Balance	7,812	9,005
Recorded Investment With No Allowance	45	96
Recorded Investment With Allowance	7,767	8,838
Total Recorded Investment	7,812	8,934
Related Allowance	3,542	3,446
Average Recorded Investment	7,947	6,379
Real Estate | Commercial - Owner Occupied
Financing Receivable, Impaired [Line Items]
Unpaid Contractual Principal Balance	4,014	6,726
Recorded Investment With No Allowance	2,947	2,178
Recorded Investment With Allowance	113	3,594
Total Recorded Investment	3,060	5,772
Related Allowance	5	339
Average Recorded Investment	4,887	7,985
Real Estate | Commercial - Investor Owned
Financing Receivable, Impaired [Line Items]
Unpaid Contractual Principal Balance	14,562	19,864
Recorded Investment With No Allowance	5,358	185
Recorded Investment With Allowance	6,234	16,577
Total Recorded Investment	11,592	16,762
Related Allowance	1,835	3,400
Average Recorded Investment	13,353	10,500
Real Estate | Construction and Land Development
Financing Receivable, Impaired [Line Items]
Unpaid Contractual Principal Balance	6,369	6,491
Recorded Investment With No Allowance	1,541	1,560
Recorded Investment With Allowance	3,846	3,135
Total Recorded Investment	5,387	4,695
Related Allowance	590	732
Average Recorded Investment	5,271	10,259
Real Estate | Residential
Financing Receivable, Impaired [Line Items]
Unpaid Contractual Principal Balance	3,246	3,132
Recorded Investment With No Allowance	1,959	1,626
Recorded Investment With Allowance	569	938
Total Recorded Investment	2,528	2,564
Related Allowance	68	259
Average Recorded Investment	2,668	4,368
Consumer & Other
Financing Receivable, Impaired [Line Items]
Unpaid Contractual Principal Balance	0	0
Recorded Investment With No Allowance	0	0
Recorded Investment With Allowance	0	0
Total Recorded Investment	0	0
Related Allowance	0	0
Average Recorded Investment	$ 0	$ 0