Annual and transition report of foreign private issuers pursuant to Section 13 or 15(d)

Maintenance rights intangible and lease premium, net (Lease premiums and related accumulated amortization) (Details)

v3.8.0.1
Maintenance rights intangible and lease premium, net (Lease premiums and related accumulated amortization) (Details) - USD ($)
$ in Thousands
Dec. 31, 2017
Dec. 31, 2016
Finite-Lived Intangible Assets [Line Items]    
Gross carrying amount $ 400,000 $ 400,000
Accumulated amortization (113,188) (82,012)
Finite-lived intangible assets 286,812 317,988
Lease Premiums [Member]    
Finite-Lived Intangible Assets [Line Items]    
Gross carrying amount 77,977 94,959
Accumulated amortization (40,718) (44,068)
Finite-lived intangible assets $ 37,259 $ 50,891