Capital (Capital Concentrations) (Details) (Capital Stock Ownership By Third Party [Member], USD $) In Thousands, unless otherwise specified	Sep. 30, 2012	Dec. 31, 2011
Capital [Line Items]
Concentration Risk Benchmark, Percent	10.00%
Sovereign Bank N.A. [Member]
Capital [Line Items]
Concentration Risk Benchmark, Percent	19.80%	16.20%
Capital Stock	$ 649,670	$ 555,370
PNC Bank N.A. [Member]
Capital [Line Items]
Concentration Risk Benchmark, Percent	12.60%
Capital Stock	413,007
Ally Bank [Member]
Capital [Line Items]
Concentration Risk Benchmark, Percent		11.20%
Capital Stock		383,865
ING Bank, FSB [Member]
Capital [Line Items]
Concentration Risk Benchmark, Percent		10.80%
Capital Stock		$ 370,360