Stockholders' Equity (Details 3) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2016
Amounts Reclassified from AOCI
Net Income Available to Common Stock and Participating Securities	$ 60,055	$ 79,261	$ 210,549	$ 228,781
Total reclassifications for period	(14,935)	(7,314)	(31,315)	(27,280)
Accumulated Other Comprehensive Income/(Loss)
Unrealized losses recorded in AOCI on securities for which Other-than-temporary impairments had been recognized in earnings in prior periods	103		103		$ 1,700
Amounts Reclassified from AOCI \| Accumulated Net Investment Gain (Loss) Including Portion Attributable to Noncontrolling Interest
Amounts Reclassified from AOCI
Realized gain on sale of securities	(14,935)	(6,829)	(30,283)	(26,795)
OTTI recognized in earnings	0	(485)	(1,032)	(485)
Net Income Available to Common Stock and Participating Securities	$ (14,935)	$ (7,314)	$ (31,315)	$ (27,280)

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Total of accumulated other comprehensive loss related to that portion of other than temporary impairment (OTTI) due to factors other than credit losses on debt securities categorized either as available-for-sale or held-to-maturity that an entity does not intend to sell and which it is not more likely than not that the entity will be required to sell before recovery of the amortized cost basis of the debt security. The amount represented by this item is net of tax, as applicable.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section 45
-Paragraph 14A
-URI http://asc.fasb.org/extlink&oid=84228862&loc=SL7669686-108580

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 45
-Paragraph 9A
-URI http://asc.fasb.org/extlink&oid=82896770&loc=SL6284427-111562

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This item represents the net total realized and unrealized gain (loss) included in earnings for the period as a result of selling or holding marketable securities categorized as trading, available-for-sale, or held-to-maturity, including the unrealized holding gain (loss) of held-to-maturity securities transferred to the trading security category and the cumulative unrealized gain (loss) which was included in other comprehensive income (a separate component of shareholders' equity) for available-for-sale securities transferred to trading securities during the period. Additionally, this item would include any gains (losses) realized during the period from the sale of investments accounted for under the cost method of accounting.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 225
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (b)(7)
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Amount after tax of income (loss) from continuing operations including portion attributable to the noncontrolling interest.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
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Amount, after deduction of tax, noncontrolling interests, dividends on preferred stock and participating securities; of income (loss) available to common shareholders.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
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-SubTopic 10
-Section 45
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Amount after tax of reclassification adjustments of other comprehensive income (loss).

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