Loans Receivable (excluding Covered Loans) (Details) (USD $)	Jun. 30, 2014	Dec. 31, 2013	Sep. 30, 2013	Sep. 30, 2012
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans receivable, gross	$ 8,447,709,000		$ 7,990,545,000
Ratio of type of loan to total loans receivable	100.00%		100.00%
Allowance for probable losses	114,150,000	114,931,000	116,741,000	133,147,000
Loans in process	303,084,000		275,577,000
Discount on acquired loans	28,480,000		34,143,000
Deferred net origination fees	36,041,000		36,054,000
Charges against loans receivable	481,755,000		462,515,000
Loans receivable, net	7,965,954,000		7,528,030,000
Single-Family Residential [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans receivable, gross	5,479,111,000		5,373,950,000
Ratio of type of loan to total loans receivable	64.90%		67.30%
Allowance for probable losses	62,360,000	63,348,000	64,184,000	81,815,000
Construction - Speculative [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans receivable, gross	126,926,000		130,778,000
Ratio of type of loan to total loans receivable	1.50%		1.60%
Allowance for probable losses	6,387,000	6,773,000	8,407,000	12,060,000
Construction - Custom [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans receivable, gross	372,789,000		302,722,000
Ratio of type of loan to total loans receivable	4.40%		3.80%
Allowance for probable losses	1,678,000	1,599,000	882,000	347,000
Land - Acquisition & Development [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans receivable, gross	91,058,000		81,660,000
Ratio of type of loan to total loans receivable	1.10%		1.10%
Allowance for probable losses	6,955,000	6,027,000	9,165,000	15,598,000
Land - Consumer Lot Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans receivable, gross	114,573,000		124,984,000
Ratio of type of loan to total loans receivable	1.40%		1.50%
Allowance for probable losses	2,862,000	2,974,000	3,552,000	4,937,000
Multi-Family [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans receivable, gross	896,799,000		835,598,000
Ratio of type of loan to total loans receivable	10.60%		10.50%
Allowance for probable losses	4,141,000	4,187,000	3,816,000	5,280,000
Commercial Real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans receivable, gross	693,421,000		625,293,000
Ratio of type of loan to total loans receivable	8.20%		7.90%
Allowance for probable losses	6,689,000	5,924,000	5,595,000	1,956,000
Commercial & Industrial [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans receivable, gross	398,181,000		326,450,000
Ratio of type of loan to total loans receivable	4.70%		4.00%
Allowance for probable losses	18,696,000	20,403,000	16,614,000	7,626,000
HELOC [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans receivable, gross	136,304,000		133,631,000
Ratio of type of loan to total loans receivable	1.60%		1.60%
Allowance for probable losses	1,015,000	975,000	1,002,000	965,000
Consumer [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans receivable, gross	138,547,000		55,479,000
Ratio of type of loan to total loans receivable	1.60%		0.70%
Allowance for probable losses	3,367,000	2,721,000	3,524,000	2,563,000
Non-Acquired Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans receivable, gross	8,167,107,000		7,641,266,000
Ratio of type of loan to total loans receivable	96.70%		95.60%
Non-Acquired Loans [Member] | Single-Family Residential [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans receivable, gross	5,466,771,000		5,359,149,000
Ratio of type of loan to total loans receivable	64.70%		67.10%
Non-Acquired Loans [Member] | Construction - Speculative [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans receivable, gross	126,926,000		130,778,000
Ratio of type of loan to total loans receivable	1.50%		1.60%
Non-Acquired Loans [Member] | Construction - Custom [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans receivable, gross	372,789,000		302,722,000
Ratio of type of loan to total loans receivable	4.40%		3.80%
Non-Acquired Loans [Member] | Land - Acquisition & Development [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans receivable, gross	88,319,000		77,775,000
Ratio of type of loan to total loans receivable	1.10%		1.10%
Non-Acquired Loans [Member] | Land - Consumer Lot Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans receivable, gross	111,919,000		121,671,000
Ratio of type of loan to total loans receivable	1.40%		1.50%
Non-Acquired Loans [Member] | Multi-Family [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans receivable, gross	893,742,000		831,684,000
Ratio of type of loan to total loans receivable	10.60%		10.40%
Non-Acquired Loans [Member] | Commercial Real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans receivable, gross	523,850,000		414,961,000
Ratio of type of loan to total loans receivable	6.20%		5.10%
Non-Acquired Loans [Member] | Commercial & Industrial [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans receivable, gross	333,552,000		243,199,000
Ratio of type of loan to total loans receivable	3.90%		3.00%
Non-Acquired Loans [Member] | HELOC [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans receivable, gross	117,177,000		112,186,000
Ratio of type of loan to total loans receivable	1.40%		1.40%
Non-Acquired Loans [Member] | Consumer [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans receivable, gross	132,062,000		47,141,000
Ratio of type of loan to total loans receivable	1.50%		0.60%
Acquired Non-Impaired Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans receivable, gross	197,254,000		250,379,000
Ratio of type of loan to total loans receivable	2.20%		3.10%
Acquired Non-Impaired Loans [Member] | Single-Family Residential [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans receivable, gross	12,014,000		14,468,000
Ratio of type of loan to total loans receivable	0.20%		0.20%
Acquired Non-Impaired Loans [Member] | Construction - Speculative [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans receivable, gross	0		0
Ratio of type of loan to total loans receivable	0.00%		0.00%
Acquired Non-Impaired Loans [Member] | Construction - Custom [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans receivable, gross	0		0
Ratio of type of loan to total loans receivable	0.00%		0.00%
Acquired Non-Impaired Loans [Member] | Land - Acquisition & Development [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans receivable, gross	1,069,000		1,489,000
Ratio of type of loan to total loans receivable	0.00%		0.00%
Acquired Non-Impaired Loans [Member] | Land - Consumer Lot Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans receivable, gross	2,654,000		3,313,000
Ratio of type of loan to total loans receivable	0.00%		0.00%
Acquired Non-Impaired Loans [Member] | Multi-Family [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans receivable, gross	3,057,000		3,914,000
Ratio of type of loan to total loans receivable	0.00%		0.10%
Acquired Non-Impaired Loans [Member] | Commercial Real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans receivable, gross	103,215,000		133,423,000
Ratio of type of loan to total loans receivable	1.10%		1.70%
Acquired Non-Impaired Loans [Member] | Commercial & Industrial [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans receivable, gross	60,349,000		75,326,000
Ratio of type of loan to total loans receivable	0.70%		0.90%
Acquired Non-Impaired Loans [Member] | HELOC [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans receivable, gross	8,469,000		10,179,000
Ratio of type of loan to total loans receivable	0.10%		0.10%
Acquired Non-Impaired Loans [Member] | Consumer [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans receivable, gross	6,427,000		8,267,000
Ratio of type of loan to total loans receivable	0.10%		0.10%
Credit Impaired Acquired Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans receivable, gross	83,348,000		98,900,000
Ratio of type of loan to total loans receivable	1.10%		1.30%
Credit Impaired Acquired Loans [Member] | Single-Family Residential [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans receivable, gross	326,000		333,000
Ratio of type of loan to total loans receivable	0.00%		0.00%
Credit Impaired Acquired Loans [Member] | Construction - Speculative [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans receivable, gross	0		0
Ratio of type of loan to total loans receivable	0.00%		0.00%
Credit Impaired Acquired Loans [Member] | Land - Acquisition & Development [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans receivable, gross	1,670,000		2,396,000
Ratio of type of loan to total loans receivable	0.00%		0.00%
Credit Impaired Acquired Loans [Member] | Multi-Family [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans receivable, gross	0		0
Ratio of type of loan to total loans receivable	0.00%		0.00%
Credit Impaired Acquired Loans [Member] | Commercial Real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans receivable, gross	66,356,000		76,909,000
Ratio of type of loan to total loans receivable	0.90%		1.10%
Credit Impaired Acquired Loans [Member] | Commercial & Industrial [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans receivable, gross	4,280,000		7,925,000
Ratio of type of loan to total loans receivable	0.10%		0.10%
Credit Impaired Acquired Loans [Member] | HELOC [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans receivable, gross	10,658,000		11,266,000
Ratio of type of loan to total loans receivable	0.10%		0.10%
Credit Impaired Acquired Loans [Member] | Consumer [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans receivable, gross	$ 58,000		$ 71,000
Ratio of type of loan to total loans receivable	0.00%		0.00%