Commitments and Contingencies - Schedule of Future Aircraft Operating Leases (Details)	Sep. 30, 2017 aircraft
Long-term Purchase Commitment [Line Items]
remainder of 2017	6
2018	10
2019	15
2020	16
2021	18
Total future aircraft to be received	65
Airbus [Member] | A320 [Member]
Long-term Purchase Commitment [Line Items]
remainder of 2017	2
2018	5
2019	1
Total future aircraft to be received	8
Airbus [Member] | A320NEO [Member]
Long-term Purchase Commitment [Line Items]
2019	14
2020	16
2021	18
Total future aircraft to be received	48
Airbus [Member] | A321 [Member]
Long-term Purchase Commitment [Line Items]
remainder of 2017	4
2018	5
Total future aircraft to be received	9