Non-Covered Loans and Allowance for Non-Covered Loan Losses (Details 2) (Plains Capital, Non-covered loans, Acquired Impaired, USD $) In Thousands, unless otherwise specified	3 Months Ended	9 Months Ended
	Sep. 30, 2013	Sep. 30, 2013	Dec. 31, 2012
Plains Capital | Non-covered loans | Acquired Impaired
Carrying values and the outstanding contractual balances of the PCI loans
Carrying amount	$ 139,224	$ 139,224	$ 166,780
Outstanding balance	187,370	187,370	222,674
Changes in the accretable yield for the acquired impaired loans
Balance, beginning of period	20,118	17,553
Additions	1,923	1,923
Increases in expected cash flows	4,697	16,834
Disposals of loans	(441)	(2,273)
Accretion	(4,854)	(12,594)
Balance, end of period	$ 21,443	$ 21,443