Covered Assets and FDIC Loss-sharing Asset (Analysis of Covered Loans) (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2014	Jun. 30, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Dec. 31, 2012
Covered Assets And FDIC Loss Sharing Asset [Line Items]
Loans, net	$ 4,755,151		$ 4,444,842
Covered Loans [Member]
Covered Assets And FDIC Loss Sharing Asset [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	273,021		341,142
Valuation discount on covered loans	29,177		43,297
Allowance for loan losses	17,933	19,801	20,174	22,737	26,135	30,056
Loans, net	225,911		277,671
Commercial Portfolio Segment [Member] | Covered Loans [Member]
Covered Assets And FDIC Loss Sharing Asset [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	52,891		72,870
Real Estate Portfolio Segment [Member] | Covered Loans [Member]
Covered Assets And FDIC Loss Sharing Asset [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	182,422		212,521
One-to-Four Family Residential Construction [Domain] | Covered Loans [Member]
Covered Assets And FDIC Loss Sharing Asset [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	5,798		14,781
Commercial and Multifamily Residential Construction [Domain] | Covered Loans [Member]
Covered Assets And FDIC Loss Sharing Asset [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	2,619		6,869
Real Estate Construction Portfolio Segment [Member] | Covered Loans [Member]
Covered Assets And FDIC Loss Sharing Asset [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	8,417		21,650
Consumer Portfolio Segment [Member] | Covered Loans [Member]
Covered Assets And FDIC Loss Sharing Asset [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	29,291		34,101
One-to-Four Family Residential [Member] | Covered Loans [Member]
Covered Assets And FDIC Loss Sharing Asset [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	34,934		41,642
Commercial and Multifamily Residential [Member] | Covered Loans [Member]
Covered Assets And FDIC Loss Sharing Asset [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	$ 147,488		$ 170,879