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Organization and Summary of Significant Accounting Policies (Equipment Held of Operating Lease) (Details) $ in Thousands | 12 Months Ended
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Dec. 31, 2017 USD ($) engine item | Dec. 31, 2016 USD ($) engine | Dec. 31, 2015 USD ($)
Equipment Held for Operating Lease |  |  |
Number of engines | engine |  | 393 |
Impairment charge | $ 24,930 | $ 9,514 | $ 9,181
Minimum |  |  |
Equipment Held for Operating Lease |  |  |
Estimated useful life | 3 years |  |
Maximum |  |  |
Equipment Held for Operating Lease |  |  |
Estimated useful life | 15 years |  |
Engines and related equipment |  |  |
Equipment Held for Operating Lease |  |  |
Number of engines | engine | 48 |  |
Aircraft |  |  |
Equipment Held for Operating Lease |  |  |
Number of aircraft | item | 3 |  |
Aircraft | Minimum |  |  |
Equipment Held for Operating Lease |  |  |
Estimated useful life | 13 years |  |
Residual value (as a percent) | 15.00% |  |
Aircraft | Maximum |  |  |
Equipment Held for Operating Lease |  |  |
Estimated useful life | 20 years |  |
Residual value (as a percent) | 17.00% |  |
Engines and aircraft |  |  |
Equipment Held for Operating Lease |  |  |
Equipment net book value | $ 80,100 |  |
Engines and aircraft | Minimum |  |  |
Equipment Held for Operating Lease |  |  |
Estimated useful life | 1 year |  |
Engines and aircraft | Maximum |  |  |
Equipment Held for Operating Lease |  |  |
Estimated useful life | 82 years |  |
New engine [Member] | Maximum |  |  |
Equipment Held for Operating Lease |  |  |
Estimated useful life | 25 years |  |
Equipment held for lease Member |  |  |
Equipment Held for Operating Lease |  |  |
Impairment charge | $ 4,400 | $ 1,800 |
Equipment held for lease Member | Engines and related equipment |  |  |
Equipment Held for Operating Lease |  |  |
Estimated useful life | 15 years |  |
Residual value (as a percent) | 55.00% |  |
Equipment held for lease Member | Spare part packages |  |  |
Equipment Held for Operating Lease |  |  |
Residual value (as a percent) | 25.00% |  |
Equipment held for lease Member | Spare part packages | Minimum |  |  |
Equipment Held for Operating Lease |  |  |
Estimated useful life | 14 years |  |
Equipment held for lease Member | Spare part packages | Maximum |  |  |
Equipment Held for Operating Lease |  |  |
Estimated useful life | 15 years |  |
Equipment held for lease Member | Engines and aircraft |  |  |
Equipment Held for Operating Lease |  |  |
Impairment charge |  |  | $ 600

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