Nature of Operations and Summary of Significant Accounting Policies - Aircraft Fleet (Details)	12 Months Ended
	Dec. 31, 2019 aircraft
Nature of Operations and Summary of Significant Accounting Policies [Line Items]
Number of daily departures	2,300
Number of aircraft held by entity	544
CRJ 200
Nature of Operations and Summary of Significant Accounting Policies [Line Items]
Number of aircraft held by entity	214
Number of seats on aircraft	50
CRJ 700
Nature of Operations and Summary of Significant Accounting Policies [Line Items]
Number of aircraft held by entity	126
CRJ 700 | Minimum
Nature of Operations and Summary of Significant Accounting Policies [Line Items]
Number of seats on aircraft	65
CRJ 700 | Maximum
Nature of Operations and Summary of Significant Accounting Policies [Line Items]
Number of seats on aircraft	76
CRJ 900
Nature of Operations and Summary of Significant Accounting Policies [Line Items]
Number of aircraft held by entity	48
CRJ 900 | Minimum
Nature of Operations and Summary of Significant Accounting Policies [Line Items]
Number of seats on aircraft	65
CRJ 900 | Maximum
Nature of Operations and Summary of Significant Accounting Policies [Line Items]
Number of seats on aircraft	76
E175
Nature of Operations and Summary of Significant Accounting Policies [Line Items]
Number of aircraft held by entity	156
E175 | Minimum
Nature of Operations and Summary of Significant Accounting Policies [Line Items]
Number of seats on aircraft	65
E175 | Maximum
Nature of Operations and Summary of Significant Accounting Policies [Line Items]
Number of seats on aircraft	76
Delta
Nature of Operations and Summary of Significant Accounting Policies [Line Items]
Number of aircraft held by entity	199
Percentage of aggregate capacity operated	41.20%
Delta | CRJ 200
Nature of Operations and Summary of Significant Accounting Policies [Line Items]
Number of aircraft held by entity	84
Delta | CRJ 700
Nature of Operations and Summary of Significant Accounting Policies [Line Items]
Number of aircraft held by entity	13
Delta | CRJ 900
Nature of Operations and Summary of Significant Accounting Policies [Line Items]
Number of aircraft held by entity	43
Delta | E175
Nature of Operations and Summary of Significant Accounting Policies [Line Items]
Number of aircraft held by entity	59
United
Nature of Operations and Summary of Significant Accounting Policies [Line Items]
Number of aircraft held by entity	183
Percentage of aggregate capacity operated	37.90%
United | CRJ 200
Nature of Operations and Summary of Significant Accounting Policies [Line Items]
Number of aircraft held by entity	99
United | CRJ 700
Nature of Operations and Summary of Significant Accounting Policies [Line Items]
Number of aircraft held by entity	19
United | E175
Nature of Operations and Summary of Significant Accounting Policies [Line Items]
Number of aircraft held by entity	65
American
Nature of Operations and Summary of Significant Accounting Policies [Line Items]
Number of aircraft held by entity	69
Percentage of aggregate capacity operated	14.30%
American | CRJ 200
Nature of Operations and Summary of Significant Accounting Policies [Line Items]
Number of aircraft held by entity	7
American | CRJ 700
Nature of Operations and Summary of Significant Accounting Policies [Line Items]
Number of aircraft held by entity	62
Alaska
Nature of Operations and Summary of Significant Accounting Policies [Line Items]
Number of aircraft held by entity	32
Percentage of aggregate capacity operated	6.60%
Alaska | E175
Nature of Operations and Summary of Significant Accounting Policies [Line Items]
Number of aircraft held by entity	32
Aircraft in scheduled service
Nature of Operations and Summary of Significant Accounting Policies [Line Items]
Number of aircraft held by entity	483
Aircraft in scheduled service | CRJ 200
Nature of Operations and Summary of Significant Accounting Policies [Line Items]
Number of aircraft held by entity	190
Aircraft in scheduled service | CRJ 700
Nature of Operations and Summary of Significant Accounting Policies [Line Items]
Number of aircraft held by entity	94
Aircraft in scheduled service | CRJ 900
Nature of Operations and Summary of Significant Accounting Policies [Line Items]
Number of aircraft held by entity	43
Aircraft in scheduled service | E175
Nature of Operations and Summary of Significant Accounting Policies [Line Items]
Number of aircraft held by entity	156
Subleased to an un-affiliated entity
Nature of Operations and Summary of Significant Accounting Policies [Line Items]
Number of aircraft held by entity	19
Subleased to an un-affiliated entity | CRJ 200
Nature of Operations and Summary of Significant Accounting Policies [Line Items]
Number of aircraft held by entity	4
Subleased to an un-affiliated entity | CRJ 700
Nature of Operations and Summary of Significant Accounting Policies [Line Items]
Number of aircraft held by entity	10
Subleased to an un-affiliated entity | CRJ 900
Nature of Operations and Summary of Significant Accounting Policies [Line Items]
Number of aircraft held by entity	5
Other
Nature of Operations and Summary of Significant Accounting Policies [Line Items]
Number of aircraft held by entity	42
Other | CRJ 200
Nature of Operations and Summary of Significant Accounting Policies [Line Items]
Number of aircraft held by entity	20
Other | CRJ 700
Nature of Operations and Summary of Significant Accounting Policies [Line Items]
Number of aircraft held by entity	22