Non-Covered Loans and Allowance for Non-Covered Loan Losses (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2013	Jun. 30, 2013	Dec. 31, 2012
Non-Covered Loans and Allowance for Non-Covered Loan Losses
Total loans	$ 3,310,224		$ 3,152,396
Allowance for loan losses	(33,180)		(3,409)
Non-covered loans, net	3,277,044		3,148,987
Non-covered loans
Non-Covered Loans and Allowance for Non-Covered Loan Losses
Total loans	3,310,224		3,152,396
Allowance for loan losses	(33,180)	(26,237)	(3,409)
Non-covered loans, net	3,277,044		3,148,987
Non-covered loans | Acquired Impaired
Non-Covered Loans and Allowance for Non-Covered Loan Losses
Total loans	139,224		166,780
Non-covered loans | Commercial and Industrial
Non-Covered Loans and Allowance for Non-Covered Loan Losses
Total loans	1,625,422		1,660,293
Allowance for loan losses	(19,507)	(13,806)	(1,845)
Non-covered loans | Real estate
Non-Covered Loans and Allowance for Non-Covered Loan Losses
Total loans	1,322,054		1,184,914
Allowance for loan losses	(7,088)	(5,339)	(977)
Non-covered loans | Construction and Land Development
Non-Covered Loans and Allowance for Non-Covered Loan Losses
Total loans	310,392		280,483
Allowance for loan losses	(6,534)	(7,050)	(582)
Non-covered loans | Consumer
Non-Covered Loans and Allowance for Non-Covered Loan Losses
Total loans	52,356		26,706
Allowance for loan losses	(51)	(42)	(5)
Non-covered loans | Consumer | Acquired Impaired
Non-Covered Loans and Allowance for Non-Covered Loan Losses
Total loans	9,363		77
Bank | Non-covered loans
Non-Covered Loans and Allowance for Non-Covered Loan Losses
Total loans	3,310,224		3,152,396
Bank | Non-covered loans | Acquired Impaired
Non-Covered Loans and Allowance for Non-Covered Loan Losses
Total loans	139,224		166,780
Bank | Non-covered loans | Consumer
Non-Covered Loans and Allowance for Non-Covered Loan Losses
Total loans	52,356		26,706
Bank | Non-covered loans | Consumer | Acquired Impaired
Non-Covered Loans and Allowance for Non-Covered Loan Losses
Total loans	9,363		77
Bank | FNB | Non-covered loans | Acquired loans
Non-Covered Loans and Allowance for Non-Covered Loan Losses
Carrying value of loans acquired	49,700
Bank | FNB | Non-covered loans | Acquired Impaired
Non-Covered Loans and Allowance for Non-Covered Loan Losses
Carrying value of loans acquired	139,200
Bank | FNB | Non-covered loans | PCI | Acquired loans
Non-Covered Loans and Allowance for Non-Covered Loan Losses
Carrying value of loans acquired	$ 17,600