Fair Value Measurements Fair Value Option Quantitative Disclosures (Details) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2012	Dec. 31, 2011
Fair Value, Option, Quantitative Disclosures [Line Items]
Loans Held-for-sale, Fair Value Disclosure	$ 1,105,985	$ 777,280
Aggregate Fair Value Under Fair Value Option [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Loans Held-for-sale, Fair Value Disclosure	1,105,985	777,280
Fair Value, Option, Loans Held as Assets, Aggregate Amount in Nonaccrual Status	0	2,129
Aggregate Unpaid Principal Balance Under Fair Value Option [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Loans Held-for-sale, Fair Value Disclosure	1,052,714	747,667
Fair Value, Option, Loans Held as Assets, Aggregate Amount in Nonaccrual Status	0	2,466
Fair Value, Option, Aggregate Fair Value Over Under Aggregate Unpaid Principal Balance [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Loans Held-for-sale, Fair Value Disclosure	53,271	29,613
Fair Value, Option, Loans Held as Assets, Aggregate Amount in Nonaccrual Status	$ 0	$ (337)