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Basis of Presentation and Significant Accounting Policies Noncontrolling Interest (Details) $ in Thousands | 12 Months Ended |
--- | --- | ---
Dec. 31, 2017 USD ($) shares | Dec. 31, 2018 USD ($) shares
Stockholders' Equity Attributable to Noncontrolling Interest | $ | $ 264,110 | $ 41,150
Preferred Stock, Shares Outstanding | shares | 0 | 0
Ambac Assurance Corporation [Member] |  |
Preferred Stock, Shares Outstanding | shares | 26,411 | 4,115
Preferred Stock, Liquidation Preference, Value | $ | $ 660,275 | $ 102,875
London Interbank Offered Rate (LIBOR) [Member] |  |
Dividend Rate on Auction Rate Preferred Shares | 200 |

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- Definition Total of all stockholders' equity (deficit) items, net of receivables from officers, directors, owners, and affiliates of the entity which is directly or indirectly attributable to that ownership interest in subsidiary equity which is not attributable to the parent (that is, noncontrolling interest, previously referred to as minority interest). + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-03(a)(24)) -URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.31) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03(22)) -URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878 + Details
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