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Loans (Net Loans Held-for-Investment) (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013
Investments In Loans [Line Items]
Document Period End Date	Jun. 30, 2015
Originated loans held-for-investment, net	$ 1,787,363		$ 1,632,494
PCI Loans	37,778		44,816
Loans acquired	378,493		265,685
Loans held-for-investment, net	2,203,634		1,942,995
Allowance for loan losses	(25,516)	$ (25,898)	(26,292)	$ (26,267)	$ (26,565)	$ (26,037)
Net loans held-for-investment	2,178,118		1,916,703
Real Estate Loans
Investments In Loans [Line Items]
Loans receivable	1,763,915		1,612,827
Commercial and industrial loans	16,693		12,945
Other loans	1,947		2,157
Total commercial and industrial and other loans	18,640		15,102
Deferred loan cost, net	4,808		4,565
Originated loans held-for-investment, net	1,787,363		1,632,494
PCI Loans			44,816
Real Estate Loans | Multifamily
Investments In Loans [Line Items]
Loans receivable	1,218,702		1,072,193
Loans held-for-investment, net	1,221,093		1,074,539
Allowance for loan losses	(13,208)	(12,698)	(12,219)	(9,880)	(9,814)	(9,374)
Real Estate Loans | Commercial real estate
Investments In Loans [Line Items]
Loans receivable	391,235		390,288
Loans held-for-investment, net	391,882		390,885
Allowance for loan losses	(7,341)	(8,483)	(9,309)	(11,882)	(12,359)	(12,619)
Real Estate Loans | One-to-four family residential mortgage
Investments In Loans [Line Items]
Loans receivable	80,557		74,401
Loans held-for-investment, net	81,177		74,990
Allowance for loan losses	(1,107)	(870)	(951)	(1,012)	(818)	(875)
Real Estate Loans | Home equity and lines of credit
Investments In Loans [Line Items]
Loans receivable	57,518		54,533
Loans held-for-investment, net	58,596		55,486
Allowance for loan losses	(941)	(842)	(901)	(993)	(958)	(860)
Real Estate Loans | Construction and land
Investments In Loans [Line Items]
Loans receivable	15,903		21,412
Loans held-for-investment, net	15,925		21,445
Allowance for loan losses	(185)	$ (218)	(266)	$ (156)	$ (227)	$ (205)
Loans acquired
Investments In Loans [Line Items]
Loans acquired	378,493		265,685
Loans held-for-investment, net	2,203,634		1,942,995
Allowance for loan losses	(25,516)		(26,292)
Loans acquired | Multifamily
Investments In Loans [Line Items]
Loans acquired	17,431		18,844
Loans acquired | Commercial real estate
Investments In Loans [Line Items]
Loans acquired	11,401		11,999
Loans acquired | One-to-four family residential mortgage
Investments In Loans [Line Items]
Loans acquired	349,661		234,478
Loans acquired | Construction and land
Investments In Loans [Line Items]
Loans acquired	$ 0		$ 364

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