Stockholders' Equity (Details 2) (USD $) In Thousands, unless otherwise specified			6 Months Ended
Jun. 30, 2012	Dec. 31, 2011	Jun. 30, 2012 Net Unrealized Gain on Available-for-Sale MBS	Jun. 30, 2012 Net Unrealized (Loss)/Gain on Swaps	Jun. 30, 2012 Accumulated Other Comprehensive Income:
Accumulated other comprehensive income/(loss)	$ 206,184	$ (58,703)	$ 55,491	$ (114,194)	$ (58,703)
Current period other comprehensive income			240,516	24,371	264,887
Accumulated other comprehensive income/(loss)	$ 206,184	$ (58,703)	$ 296,007	$ (89,823)	$ 206,184

Accumulated change in equity from transactions and other events and circumstances from non-owner sources, net of tax effect, at period end. Excludes Net Income (Loss), and accumulated changes in equity from transactions resulting from investments by owners and distributions to owners. Includes foreign currency translation items, certain pension adjustments, unrealized gains and losses on certain investments in debt and equity securities, other than temporary impairment (OTTI) losses related to factors other than credit losses on available-for-sale and held-to-maturity debt securities that an entity does not intend to sell and it is not more likely than not that the entity will be required to sell before recovery of the amortized cost basis, as well as changes in the fair value of derivatives related to the effective portion of a designated cash flow hedge.

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+ Details

- Definition

This element represents Other Comprehensive Income or Loss, Net of Tax, for the period. Includes deferred gains or losses on qualifying hedges, unrealized holding gains or losses on available-for-sale securities, minimum pension liability, and cumulative translation adjustment. While for technical reasons this element has no balance attribute, the default assumption is a credit balance consistent with its label.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

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-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

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+ Details