Portfolio Loans Not Covered by Loss Share ("Non-covered") - Summary of Recorded Investment in Non-covered Loans by Portfolio Class and Category Based on Impairment Method (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended	6 Months Ended
	Jun. 30, 2013	Jun. 30, 2013	Dec. 31, 2012	Jun. 30, 2013 Non-Covered Loans	Mar. 31, 2013 Non-Covered Loans	Dec. 31, 2012 Non-Covered Loans	Jun. 30, 2013 Non-Covered Loans Commercial & Industrial	Mar. 31, 2013 Non-Covered Loans Commercial & Industrial	Dec. 31, 2012 Non-Covered Loans Commercial & Industrial	Jun. 30, 2013 Non-Covered Loans Real Estate	Dec. 31, 2012 Non-Covered Loans Real Estate	Jun. 30, 2013 Non-Covered Loans Real Estate Commercial Real Estate Owner Occupied	Mar. 31, 2013 Non-Covered Loans Real Estate Commercial Real Estate Owner Occupied	Dec. 31, 2012 Non-Covered Loans Real Estate Commercial Real Estate Owner Occupied	Jun. 30, 2013 Non-Covered Loans Real Estate Commercial Real Estate Investor Owned	Mar. 31, 2013 Non-Covered Loans Real Estate Commercial Real Estate Investor Owned	Dec. 31, 2012 Non-Covered Loans Real Estate Commercial Real Estate Investor Owned	Jun. 30, 2013 Non-Covered Loans Real Estate Construction and Land Development	Mar. 31, 2013 Non-Covered Loans Real Estate Construction and Land Development	Dec. 31, 2012 Non-Covered Loans Real Estate Construction and Land Development	Jun. 30, 2013 Non-Covered Loans Real Estate Residential Real Estate	Mar. 31, 2013 Non-Covered Loans Real Estate Residential Real Estate	Dec. 31, 2012 Non-Covered Loans Real Estate Residential Real Estate	Jun. 30, 2013 Non-Covered Loans Consumer & Other	Mar. 31, 2013 Non-Covered Loans Consumer & Other	Dec. 31, 2012 Non-Covered Loans Consumer & Other	Jun. 30, 2013 Non-Covered Loans Qualitative Adjustment	Mar. 31, 2013 Non-Covered Loans Qualitative Adjustment	Dec. 31, 2012 Non-Covered Loans Qualitative Adjustment
Summary of Recorded Investment in Non-covered Loans by Portfolio Class and Category Based on Impairment Method [Line Items]
Impaired Financing Receivable, Interest Income, Cash Basis Method	$ 9	$ 24
Allowance for Loan Losses - Ending Balance:
Individually evaluated for impairment				4,331		8,176	3,221		3,446			0		339	591		3,400	452		732	67		259	0		0	0		0
Collectively evaluated for impairment				23,288		26,154	6,453		6,618			3,910		3,853	5,624		7,003	3,363		4,507	1,779		1,767	44		31	2,115		2,375
Total				27,619	32,452	34,330	9,674	10,276	10,064			3,910	4,064	4,192	6,215	8,640	10,403	3,815	4,936	5,239	1,846	2,111	2,026	44	43	31	2,115	2,382	2,375
Loans - Ending Balance:
Individually evaluated for Impairment				25,948		38,727	6,681		8,934			761		5,772	11,678		16,762	4,396		4,695	2,432		2,564	0		0	0		0
Collectively evaluated for impairment				2,052,620		2,067,312	956,239		953,950			337,185		327,470	436,076		469,705	143,492		156,216	148,666		142,994	30,962		16,977	0		0
Total				2,077,826		2,106,028	962,920		962,884	1,084,686	1,126,178	337,946		333,242	447,754		486,467	147,888		160,911	151,098		145,558	30,220		16,966
Total	$ 2,078,568	$ 2,078,568	$ 2,106,039	$ 2,078,568		$ 2,106,039																		$ 30,962		$ 16,977	$ 0		$ 0