Covered Assets and FDIC Loss-sharing Asset Covered Loans - Credit Quality Indicator (Details) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Net Reported Amount	$ 4,467,981		$ 2,864,803
Covered Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	424,058		500,794
Valuation discount on covered loans	59,262		79,401
Loans and Leases Receivable, Allowance	26,135	29,489	30,056	31,784	20,504	4,944
Loans and Leases Receivable, Net Reported Amount	338,661		391,337
Covered Loans [Member] | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	318,357		356,520
Covered Loans [Member] | Special Mention [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	9,489		11,003
Covered Loans [Member] | Substandard [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	95,704		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	481		0
Real Estate Portfolio Segment [Member] | Covered Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	251,523		290,256
Real Estate Portfolio Segment [Member] | Covered Loans [Member] | One-to-Four Family Residential [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	47,256		57,150
Real Estate Portfolio Segment [Member] | Covered Loans [Member] | Commercial Land [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	24,063		26,628
Real Estate Portfolio Segment [Member] | Covered Loans [Member] | Income Property Multifamily [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	91,461		105,384
Real Estate Portfolio Segment [Member] | Covered Loans [Member] | Owner Occupied [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	88,743		101,094
Real Estate Portfolio Segment [Member] | Covered Loans [Member] | Pass [Member] | One-to-Four Family Residential [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	37,786		44,782
Real Estate Portfolio Segment [Member] | Covered Loans [Member] | Pass [Member] | Commercial Land [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	14,722		16,336
Real Estate Portfolio Segment [Member] | Covered Loans [Member] | Pass [Member] | Income Property Multifamily [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	73,940		81,205
Real Estate Portfolio Segment [Member] | Covered Loans [Member] | Pass [Member] | Owner Occupied [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	72,372		82,222
Real Estate Portfolio Segment [Member] | Covered Loans [Member] | Special Mention [Member] | One-to-Four Family Residential [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	1,607		1,344
Real Estate Portfolio Segment [Member] | Covered Loans [Member] | Special Mention [Member] | Commercial Land [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	0		0
Real Estate Portfolio Segment [Member] | Covered Loans [Member] | Special Mention [Member] | Income Property Multifamily [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	1,538		864
Real Estate Portfolio Segment [Member] | Covered Loans [Member] | Special Mention [Member] | Owner Occupied [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	939		3,318
Real Estate Portfolio Segment [Member] | Covered Loans [Member] | Substandard [Member] | One-to-Four Family Residential [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	7,863		11,024
Real Estate Portfolio Segment [Member] | Covered Loans [Member] | Substandard [Member] | Commercial Land [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	9,341		10,292
Real Estate Portfolio Segment [Member] | Covered Loans [Member] | Substandard [Member] | Income Property Multifamily [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	15,983		23,315
Real Estate Portfolio Segment [Member] | Covered Loans [Member] | Substandard [Member] | Owner Occupied [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	15,432		15,554
Real Estate Portfolio Segment [Member] | Covered Loans [Member] | Doubtful [Member] | One-to-Four Family Residential [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	0		0
Real Estate Portfolio Segment [Member] | Covered Loans [Member] | Doubtful [Member] | Commercial Land [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	0		0
Real Estate Portfolio Segment [Member] | Covered Loans [Member] | Doubtful [Member] | Income Property Multifamily [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	0		0
Real Estate Portfolio Segment [Member] | Covered Loans [Member] | Doubtful [Member] | Owner Occupied [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	0		0
Real Estate Portfolio Segment [Member] | Covered Loans [Member] | Unlikely to be Collected Financing Receivable [Member] | One-to-Four Family Residential [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	0		0
Real Estate Portfolio Segment [Member] | Covered Loans [Member] | Unlikely to be Collected Financing Receivable [Member] | Commercial Land [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	0		0
Real Estate Portfolio Segment [Member] | Covered Loans [Member] | Unlikely to be Collected Financing Receivable [Member] | Income Property Multifamily [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	0		0
Real Estate Portfolio Segment [Member] | Covered Loans [Member] | Unlikely to be Collected Financing Receivable [Member] | Owner Occupied [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	0		0
Real Estate Construction Portfolio Segment [Member] | Covered Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	30,135		40,649
Real Estate Construction Portfolio Segment [Member] | Covered Loans [Member] | One-to-Four Family Residential [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	18,433		25,398
Real Estate Construction Portfolio Segment [Member] | Covered Loans [Member] | Income Property Multifamily [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	10,259		12,320
Real Estate Construction Portfolio Segment [Member] | Covered Loans [Member] | Owner Occupied [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	1,443		2,931
Real Estate Construction Portfolio Segment [Member] | Covered Loans [Member] | Land And Acquisition [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	11,501		13,833
Real Estate Construction Portfolio Segment [Member] | Covered Loans [Member] | Residential Construction [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	6,932		11,565
Real Estate Construction Portfolio Segment [Member] | Covered Loans [Member] | Pass [Member] | Income Property Multifamily [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	3,890		4,419
Real Estate Construction Portfolio Segment [Member] | Covered Loans [Member] | Pass [Member] | Owner Occupied [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	1,090		1,107
Real Estate Construction Portfolio Segment [Member] | Covered Loans [Member] | Pass [Member] | Land And Acquisition [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	4,813		4,817
Real Estate Construction Portfolio Segment [Member] | Covered Loans [Member] | Pass [Member] | Residential Construction [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	2,598		6,050
Real Estate Construction Portfolio Segment [Member] | Covered Loans [Member] | Special Mention [Member] | Income Property Multifamily [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	0		0
Real Estate Construction Portfolio Segment [Member] | Covered Loans [Member] | Special Mention [Member] | Owner Occupied [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	0		0
Real Estate Construction Portfolio Segment [Member] | Covered Loans [Member] | Special Mention [Member] | Land And Acquisition [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	2,777		3,273
Real Estate Construction Portfolio Segment [Member] | Covered Loans [Member] | Special Mention [Member] | Residential Construction [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	165		0
Real Estate Construction Portfolio Segment [Member] | Covered Loans [Member] | Substandard [Member] | Income Property Multifamily [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	6,369		7,901
Real Estate Construction Portfolio Segment [Member] | Covered Loans [Member] | Substandard [Member] | Owner Occupied [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	353		1,824
Real Estate Construction Portfolio Segment [Member] | Covered Loans [Member] | Substandard [Member] | Land And Acquisition [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	3,430		5,743
Real Estate Construction Portfolio Segment [Member] | Covered Loans [Member] | Substandard [Member] | Residential Construction [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	4,169		5,515
Real Estate Construction Portfolio Segment [Member] | Covered Loans [Member] | Doubtful [Member] | Income Property Multifamily [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	0		0
Real Estate Construction Portfolio Segment [Member] | Covered Loans [Member] | Doubtful [Member] | Owner Occupied [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	0		0
Real Estate Construction Portfolio Segment [Member] | Covered Loans [Member] | Doubtful [Member] | Land And Acquisition [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	0		0
Real Estate Construction Portfolio Segment [Member] | Covered Loans [Member] | Doubtful [Member] | Residential Construction [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	0		0
Real Estate Construction Portfolio Segment [Member] | Covered Loans [Member] | Unlikely to be Collected Financing Receivable [Member] | Income Property Multifamily [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	0		0
Real Estate Construction Portfolio Segment [Member] | Covered Loans [Member] | Unlikely to be Collected Financing Receivable [Member] | Owner Occupied [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	0		0
Real Estate Construction Portfolio Segment [Member] | Covered Loans [Member] | Unlikely to be Collected Financing Receivable [Member] | Land And Acquisition [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	481		0
Real Estate Construction Portfolio Segment [Member] | Covered Loans [Member] | Unlikely to be Collected Financing Receivable [Member] | Residential Construction [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	0		0
Consumer Portfolio Segment [Member] | Covered Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	39,981		44,516
Consumer Portfolio Segment [Member] | Covered Loans [Member] | Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	35,637		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	187		381
Consumer Portfolio Segment [Member] | Covered Loans [Member] | Substandard [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	4,130		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
Commercial Portfolio Segment [Member] | Covered Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	102,419		125,373
Commercial Portfolio Segment [Member] | Covered Loans [Member] | Secured Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	98,182		118,594
Commercial Portfolio Segment [Member] | Covered Loans [Member] | Unsecured Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	4,237		6,779
Commercial Portfolio Segment [Member] | Covered Loans [Member] | Pass [Member] | Secured Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	67,773		71,621
Commercial Portfolio Segment [Member] | Covered Loans [Member] | Pass [Member] | Unsecured Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	3,736		4,988
Commercial Portfolio Segment [Member] | Covered Loans [Member] | Special Mention [Member] | Secured Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	1,880		1,823
Commercial Portfolio Segment [Member] | Covered Loans [Member] | Special Mention [Member] | Unsecured Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	396		0
Commercial Portfolio Segment [Member] | Covered Loans [Member] | Substandard [Member] | Secured Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	28,529		45,150
Commercial Portfolio Segment [Member] | Covered Loans [Member] | Substandard [Member] | Unsecured Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	105		1,791
Commercial Portfolio Segment [Member] | Covered Loans [Member] | Doubtful [Member] | Secured Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	0		0
Commercial Portfolio Segment [Member] | Covered Loans [Member] | Doubtful [Member] | Unsecured Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	0		0
Commercial Portfolio Segment [Member] | Covered Loans [Member] | Unlikely to be Collected Financing Receivable [Member] | Secured Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	0		0
Commercial Portfolio Segment [Member] | Covered Loans [Member] | Unlikely to be Collected Financing Receivable [Member] | Unsecured Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	$ 0		$ 0