Commitments and Contingencies - Additional Information (Detail) $ in Millions	6 Months Ended	12 Months Ended
	Jun. 30, 2016 USD ($) Aircraft Land_Parcel	Dec. 31, 2015 Aircraft	Dec. 31, 2014 Aircraft
Long-term Purchase Commitment [Line Items]
Number of aircrafts delivered | Aircraft		1
Total aircraft deposits	$ 2.7
Aggregate estimated probable liability environmental matters	$ 0.2
Number of parcels of land exists | Land_Parcel	2
Aggregate commitments under operating leases	$ 268.3
Operational lease payable	25.1
Lease commitment for aircraft	254.5
Facility lease commitments	13.8
2016 [Member]
Long-term Purchase Commitment [Line Items]
Aggregate purchase price for aircraft	67.8
2017 [Member]
Long-term Purchase Commitment [Line Items]
Aggregate purchase price for aircraft	55.7
2018 [Member]
Long-term Purchase Commitment [Line Items]
Aggregate purchase price for aircraft	127.0
2019 [Member]
Long-term Purchase Commitment [Line Items]
Aggregate purchase price for aircraft	150.4
2020 [Member]
Long-term Purchase Commitment [Line Items]
Aggregate purchase price for aircraft	22.7
Heavy Aircraft [Member]
Long-term Purchase Commitment [Line Items]
Option to purchase additional number of aircrafts | Aircraft			6
Number of aircraft orders cancelled previously scheduled for delivery | Aircraft		4
Aggregate purchase price for aircraft	$ 26.7
Number of aircraft purchased | Aircraft	1