CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
OPERATING REVENUES:
Total operating revenues	$ 534,555	$ 729,936
OPERATING EXPENSES:
Salaries, wages and benefits	219,842	249,160
Depreciation and amortization	109,597	111,708
Payroll support grant	(193,173)
Other operating expenses	54,488	69,422
Total operating expenses	453,713	663,615
OPERATING INCOME	80,842	66,321
OTHER INCOME (EXPENSE):
Interest income	284	2,564
Interest expense	(31,354)	(30,204)
Other income, net	216	398
Total other expense, net	(30,854)	(27,242)
INCOME BEFORE INCOME TAXES	49,988	39,079
PROVISION FOR INCOME TAXES	14,088	9,091
NET INCOME	$ 35,900	$ 29,988
BASIC EARNINGS PER SHARE (in dollars per share)	$ 0.71	$ 0.60
DILUTED EARNINGS PER SHARE (in dollars per share)	$ 0.71	$ 0.59
Weighted average common shares:
Basic (in shares)	50,286	50,277
Diluted (in shares)	50,727	50,559
COMPREHENSIVE INCOME:
Net income	$ 35,900	$ 29,988
TOTAL COMPREHENSIVE INCOME	35,900	29,988
Flying agreements
OPERATING REVENUES:
Total operating revenues	511,191	709,494
Lease, airport services and other
OPERATING REVENUES:
Total operating revenues	23,364	20,442
Aircraft maintenance, materials and repairs
OPERATING EXPENSES:
Total operating expenses	203,827	160,216
Airport-related expenses
OPERATING EXPENSES:
Total operating expenses	24,448	30,640
Aircraft fuel
OPERATING EXPENSES:
Total operating expenses	19,194	25,413
Aircraft rentals
OPERATING EXPENSES:
Total operating expenses	$ 15,490	$ 17,056