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Organization and Summary of Significant Accounting Policies (Investments and Lease Costs) (Details) - USD ($) $ in Millions | 12 Months Ended
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Dec. 31, 2016 | Dec. 31, 2015 | Dec. 31, 2014
Initial Direct Costs associated with Leases |  |  |
Amortization of initial direct costs associated with leases | $ 1.6 | $ 1.6 | $ 1.5
Maintenance Rights [Abstrac] |  |  |
Maintenance right assets | $ 17.7 | $ 12.1 |
WOLF |  |  |
Investments |  |  |
Previously held interest (as a percent) | 50.00% |  |
WMES |  |  |
Investments |  |  |
Ownership interest (as a percent) | 50.00% |  |

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