Investments (Details) (USD $) In Thousands	Jun. 30, 2011	Dec. 31, 2010
Investment Securities, Available-for-Sale
Amortized Cost	$ 1,437,349	$ 1,512,808
Gross Unrealized Gains	37,893	18,524
Gross Unrealized Losses	(2,499)	(8,421)
Investment Securities, Available-for-Sale at Estimated Fair Value	1,472,743	1,522,911
Agency callable notes [Member]
Investment Securities, Available-for-Sale
Amortized Cost	124,984	164,219
Gross Unrealized Gains	575	418
Gross Unrealized Losses	(569)	(1,749)
Investment Securities, Available-for-Sale at Estimated Fair Value	124,990	162,888
Agency debt [Member]
Investment Securities, Available-for-Sale
Amortized Cost	55,918	102,263
Gross Unrealized Gains	1,046	1,167
Gross Unrealized Losses	0	0
Investment Securities, Available-for-Sale at Estimated Fair Value	56,964	103,430
Agency discount notes [Member]
Investment Securities, Available-for-Sale
Amortized Cost	0	164,917
Gross Unrealized Gains	0	57
Gross Unrealized Losses	0	0
Investment Securities, Available-for-Sale at Estimated Fair Value	0	164,974
Agency MBS [Member]
Investment Securities, Available-for-Sale
Amortized Cost	1,110,767	860,441
Gross Unrealized Gains	23,456	15,035
Gross Unrealized Losses	(696)	(5,321)
Investment Securities, Available-for-Sale at Estimated Fair Value	1,133,527	870,155
Asset-backed Securities [Member]
Investment Securities, Available-for-Sale
Amortized Cost	18,874	0
Gross Unrealized Gains	1,016	0
Gross Unrealized Losses	0	0
Investment Securities, Available-for-Sale at Estimated Fair Value	19,890	0
Collateralized loan obligation
Investment Securities, Available-for-Sale
Amortized Cost	10,285	12,249
Gross Unrealized Gains	10,161	0
Gross Unrealized Losses	0	0
Investment Securities, Available-for-Sale at Estimated Fair Value	20,446	12,249
Corporate debt [Member]
Investment Securities, Available-for-Sale
Amortized Cost	5,730	5,013
Gross Unrealized Gains	63	122
Gross Unrealized Losses	(15)	0
Investment Securities, Available-for-Sale at Estimated Fair Value	5,778	5,135
Equity securities [Member]
Investment Securities, Available-for-Sale
Amortized Cost	202	202
Gross Unrealized Gains	318	61
Gross Unrealized Losses	0	0
Investment Securities, Available-for-Sale at Estimated Fair Value	520	263
Municipal Bonds [Member]
Investment Securities, Available-for-Sale
Amortized Cost	3,235	0
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	0
Investment Securities, Available-for-Sale at Estimated Fair Value	3,235	0
Non-agency MBS [Member]
Investment Securities, Available-for-Sale
Amortized Cost	87,558	112,917
Gross Unrealized Gains	1,258	1,640
Gross Unrealized Losses	(1,203)	(873)
Investment Securities, Available-for-Sale at Estimated Fair Value	87,613	113,684
U.S. Treasury and agency securities [Member]
Investment Securities, Available-for-Sale
Amortized Cost	19,796	90,587
Gross Unrealized Gains	0	24
Gross Unrealized Losses	(16)	(478)
Investment Securities, Available-for-Sale at Estimated Fair Value	$ 19,780	$ 90,133

For an unclassified balance sheet, this item represents investments in debt and equity securities which are categorized neither as held-to-maturity nor trading.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 45
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6871852&loc=d3e26610-111562

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 115
-Paragraph 12
-Subparagraph b
-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.

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name FASB Staff Position (FSP)
-Number FAS115-1/124-1
-Paragraph 15E
-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.

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 133
-Paragraph 22
-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.

Reference 5: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name FASB Staff Position (FSP)
-Number FAS115-1/124-1
-Paragraph 15D
-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.

Reference 6: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 115
-Paragraph 13
-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.

Reference 7: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name FASB Staff Position (FSP)
-Number FAS115-1/124-1
-Paragraph 15C
-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.

Reference 8: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 115
-Paragraph 14
-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.

Reference 9: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 115
-Paragraph 16
-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.

Reference 10: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 25
-Paragraph 1
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=6379932&loc=d3e22054-111558

+ Details

- Definition

This item represents the cost of debt and equity securities, which are categorized neither as held-to-maturity nor trading, net of adjustments including accretion, amortization, collection of cash, previous other-than-temporary impairments recognized in earnings (less any cumulative-effect adjustments recognized, as defined), and fair value hedge accounting adjustments, if any.

+ References+ Details

- Definition

This item represents the gross unrealized gains for securities, at a point in time, which are categorized neither as held-to-maturity nor trading securities.

+ References+ Details