Fair Value Measurements (Details 4) (USD $)	Sep. 30, 2013 Non-covered loans	Sep. 30, 2013 PCI loans Covered loans	Sep. 30, 2013 PlainsCapital PCI loans Non-covered loans	Dec. 31, 2012 PlainsCapital PCI loans Non-covered loans	Sep. 13, 2013 FNB Bank	Sep. 13, 2013 FNB Covered loans Bank	Sep. 13, 2013 FNB PCI loans Bank	Sep. 30, 2013 FNB PCI loans Non-covered loans Bank	Sep. 30, 2013 Level 3 PCI loans Covered loans	Sep. 30, 2013 Level 3 PCI loans Non-covered loans	Sep. 13, 2013 Non-recurring Level 2 FNB Covered loans Bank	Sep. 30, 2013 Non-recurring Level 2 Estimated fair value Covered loans	Sep. 30, 2013 Non-recurring Level 2 Estimated fair value Non-covered loans	Nov. 30, 2012 Non-recurring Level 3 PlainsCapital PCI loans	Sep. 13, 2013 Non-recurring Level 3 FNB PCI loans
Fair value measurements
Fair value of loans acquired					$ 1,151,336,000		$ 807,448,000							$ 172,900,000	$ 807,400,000
Carrying value of loans acquired		782,560,000	139,224,000	166,780,000				139,200,000	782,600,000	17,600,000
Allowance for loan losses	3,011,000									3,000,000
Fair value of PCI loans acquired										136,200,000
Acquired OREO						120,985,000					121,000,000
Other real estate owned												$ 119,700,000	$ 7,000,000