Covered Assets and FDIC Loss-sharing Asset Covered Loans - Credit Quality Indicator (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2013	Jun. 30, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Dec. 31, 2011
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Net Reported Amount	$ 4,440,048		$ 2,864,803
Covered Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	374,342		500,794
Valuation discount on covered loans	49,445		79,401
Loans and Leases Receivable, Allowance	22,737	26,135	30,056	29,157	31,784	4,944
Loans and Leases Receivable, Net Reported Amount	302,160		391,337
Covered Loans [Member] | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	286,795		356,520
Covered Loans [Member] | Special Mention [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	12,188		11,003
Covered Loans [Member] | Substandard [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	75,332		133,271
Covered Loans [Member] | Doubtful [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	27		0
Covered Loans [Member] | Unlikely to be Collected Financing Receivable [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	0		0
Real Estate Portfolio Segment [Member] | Covered Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	226,600		290,256
Real Estate Construction Portfolio Segment [Member] | Covered Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	23,164		40,649
Consumer Portfolio Segment [Member] | Covered Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	37,212		44,516
Consumer Portfolio Segment [Member] | Covered Loans [Member] | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	33,421		38,973
Consumer Portfolio Segment [Member] | Covered Loans [Member] | Special Mention [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	35		381
Consumer Portfolio Segment [Member] | Covered Loans [Member] | Substandard [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	3,729		5,162
Consumer Portfolio Segment [Member] | Covered Loans [Member] | Doubtful [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	27		0
Consumer Portfolio Segment [Member] | Covered Loans [Member] | Unlikely to be Collected Financing Receivable [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	0		0
Secured Loans [Member] | Covered Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	83,857		118,594
Secured Loans [Member] | Covered Loans [Member] | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	56,973		71,621
Secured Loans [Member] | Covered Loans [Member] | Special Mention [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	2,859		1,823
Secured Loans [Member] | Covered Loans [Member] | Substandard [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	24,025		45,150
Secured Loans [Member] | Covered Loans [Member] | Doubtful [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	0		0
Secured Loans [Member] | Covered Loans [Member] | Unlikely to be Collected Financing Receivable [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	0		0
Unsecured Loans [Member] | Covered Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	3,509		6,779
Unsecured Loans [Member] | Covered Loans [Member] | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	3,018		4,988
Unsecured Loans [Member] | Covered Loans [Member] | Special Mention [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	396		0
Unsecured Loans [Member] | Covered Loans [Member] | Substandard [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	95		1,791
Unsecured Loans [Member] | Covered Loans [Member] | Doubtful [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	0		0
Unsecured Loans [Member] | Covered Loans [Member] | Unlikely to be Collected Financing Receivable [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	0		0
One-to-Four Family Residential [Member] | Covered Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	44,966		57,150
One-to-Four Family Residential [Member] | Covered Loans [Member] | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	36,419		44,782
One-to-Four Family Residential [Member] | Covered Loans [Member] | Special Mention [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	1,854		1,344
One-to-Four Family Residential [Member] | Covered Loans [Member] | Substandard [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	6,693		11,024
One-to-Four Family Residential [Member] | Covered Loans [Member] | Doubtful [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	0		0
One-to-Four Family Residential [Member] | Covered Loans [Member] | Unlikely to be Collected Financing Receivable [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	0		0
Commercial Land [Member] | Covered Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	19,979		26,628
Commercial Land [Member] | Covered Loans [Member] | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	11,978		16,336
Commercial Land [Member] | Covered Loans [Member] | Special Mention [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	205		0
Commercial Land [Member] | Covered Loans [Member] | Substandard [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	7,796		10,292
Commercial Land [Member] | Covered Loans [Member] | Doubtful [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	0		0
Commercial Land [Member] | Covered Loans [Member] | Unlikely to be Collected Financing Receivable [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	0		0
Income Property Multifamily [Member] | Covered Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	75,609		105,384
Income Property Multifamily [Member] | Covered Loans [Member] | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	59,736		81,205
Income Property Multifamily [Member] | Covered Loans [Member] | Special Mention [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	3,966		864
Income Property Multifamily [Member] | Covered Loans [Member] | Substandard [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	11,907		23,315
Income Property Multifamily [Member] | Covered Loans [Member] | Doubtful [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	0		0
Income Property Multifamily [Member] | Covered Loans [Member] | Unlikely to be Collected Financing Receivable [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	0		0
Owner Occupied [Member] | Covered Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	86,046		101,094
Owner Occupied [Member] | Covered Loans [Member] | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	73,045		82,222
Owner Occupied [Member] | Covered Loans [Member] | Special Mention [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	114		3,318
Owner Occupied [Member] | Covered Loans [Member] | Substandard [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	12,887		15,554
Owner Occupied [Member] | Covered Loans [Member] | Doubtful [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	0		0
Owner Occupied [Member] | Covered Loans [Member] | Unlikely to be Collected Financing Receivable [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	0		0
Land And Acquisition [Member] | Covered Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	9,845		13,833
Land And Acquisition [Member] | Covered Loans [Member] | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	4,688		4,817
Land And Acquisition [Member] | Covered Loans [Member] | Special Mention [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	2,759		3,273
Land And Acquisition [Member] | Covered Loans [Member] | Substandard [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	2,398		5,743
Land And Acquisition [Member] | Covered Loans [Member] | Doubtful [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	0		0
Land And Acquisition [Member] | Covered Loans [Member] | Unlikely to be Collected Financing Receivable [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	0		0
Residential Construction [Member] | Covered Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	6,173		11,565
Residential Construction [Member] | Covered Loans [Member] | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	2,587		6,050
Residential Construction [Member] | Covered Loans [Member] | Special Mention [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	0		0
Residential Construction [Member] | Covered Loans [Member] | Substandard [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	3,586		5,515
Residential Construction [Member] | Covered Loans [Member] | Doubtful [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	0		0
Residential Construction [Member] | Covered Loans [Member] | Unlikely to be Collected Financing Receivable [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	0		0
Income Property Multifamily Construction [Member] | Covered Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	5,783		12,320
Income Property Multifamily Construction [Member] | Covered Loans [Member] | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	3,847		4,419
Income Property Multifamily Construction [Member] | Covered Loans [Member] | Special Mention [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	0		0
Income Property Multifamily Construction [Member] | Covered Loans [Member] | Substandard [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	1,936		7,901
Income Property Multifamily Construction [Member] | Covered Loans [Member] | Doubtful [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	0		0
Income Property Multifamily Construction [Member] | Covered Loans [Member] | Unlikely to be Collected Financing Receivable [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	0		0
Owner Occupied Construction [Member] | Covered Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	1,363		2,931
Owner Occupied Construction [Member] | Covered Loans [Member] | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	1,083		1,107
Owner Occupied Construction [Member] | Covered Loans [Member] | Special Mention [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	0		0
Owner Occupied Construction [Member] | Covered Loans [Member] | Substandard [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	280		1,824
Owner Occupied Construction [Member] | Covered Loans [Member] | Doubtful [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	0		0
Owner Occupied Construction [Member] | Covered Loans [Member] | Unlikely to be Collected Financing Receivable [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	0		0
Commercial Portfolio Segment [Member] | Covered Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	$ 87,366		$ 125,373