Investment Securities (Narrative) (Details) (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Schedule of Investments [Line Items]
Investment Securities Available-for-Sale: Fair Value	$ 496,815,000	$ 414,507,000
Tranche	Super Senior
Debt Securities Realized Loss	318,000
Other Than Temporary Impairment Losses Debt Securities	484,000
Debt Security Percent Of Par	15.3
Debt Security Par Value	3,200,000
Available-for-sale Debt Securities, Amortized Cost Basis	2,100,000
Proceeds from Sale and Maturity of Available-for-sale Securities	130,100,000	25,480,000	644,100,000
Available-for-sale Securities, Gross Realized Gains (Losses), Sale Proceeds	2,905,000	4,045,000	4,872,000
Available-for-sale Securities, Gross Realized Gain (Loss)	893,000	411,000	635,000
Other than Temporary Impairment Losses, Investments, Held-to-maturity Securities	870,000	342,000
Excess subordination as a percentage of remainging performing collateral	(49.30%)
Available-for-sale Securities Pledged as Collateral	96,100,000	98,700,000
Parent Company [Member]
Schedule of Investments [Line Items]
Investment Securities Available-for-Sale: Fair Value	543,000	419,000
Proceeds from Sale and Maturity of Available-for-sale Securities	375,000
Available-for-sale Securities, Gross Realized Gain (Loss)	26,000		(97,000)
ALESCO Preferred Funding VII [Member]
Schedule of Investments [Line Items]
Gain (Loss) on Sales of Mortgage Backed Securities (MBS)	18,000
Other Asset Impairment Charges	68,000
Collateralized mortgage obligations [Member]
Schedule of Investments [Line Items]
Investment Securities Available-for-Sale: Fair Value	2,120,000	1,899,000
Tranche	Super Senior
Debt Securities Realized Loss	318,000,000
Other Than Temporary Impairment Losses Debt Securities	484,000
Debt Security Percent Of Par	15,300,000
Debt Security Par Value	3,200,000
Available-for-sale Debt Securities, Amortized Cost Basis	$ 2,100,000
Sale Of Debt Security Transaction Date	Jan. 01, 2013
Collateralized mortgage obligations [Member] | California [Member]
Schedule of Investments [Line Items]
Geographic Concentration	18.20%
Collateralized mortgage obligations [Member] | Arizona [Member]
Schedule of Investments [Line Items]
Geographic Concentration	10.50%
Collateralized mortgage obligations [Member] | Virginia [Member]
Schedule of Investments [Line Items]
Geographic Concentration	6.10%
Collateralized mortgage obligations [Member] | Florida [Member]
Schedule of Investments [Line Items]
Geographic Concentration	6.50%
Collateralized mortgage obligations [Member] | Nevada [Member]
Schedule of Investments [Line Items]
Geographic Concentration	6.30%
Standard & Poor's, AAA Rating [Member] | Collateralized mortgage obligations [Member]
Schedule of Investments [Line Items]
Debt Securities Number Owned	1
Standard & Poor's, AA Rating [Member] | Collateralized mortgage obligations [Member]
Schedule of Investments [Line Items]
Debt Securities Number Owned	1