Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
REVENUES	$ 203,607	$ 253,211	$ 406,647	$ 491,128
OPERATING EXPENSES
Salaries, wages and benefits	74,049	65,833	144,832	138,319
Fuel	5,913	32,258	11,701	67,099
Maintenance, materials and repairs	36,817	37,588	73,683	67,870
Depreciation and amortization	41,620	37,781	81,624	74,223
Travel	7,288	6,820	13,920	14,186
Contracted ground and aviation services	2,444	32,151	4,828	52,838
Rent	3,760	3,753	6,990	7,039
Landing and ramp	1,311	4,357	2,459	9,656
Insurance	1,420	955	2,777	2,217
Other operating expenses	5,087	8,590	12,292	16,626
Operating Expenses	179,709	230,086	355,106	450,073
OPERATING INCOME	23,898	23,125	51,541	41,055
OTHER INCOME (EXPENSE)
Interest income	54	16	77	48
Non-service component of retiree benefit costs	2,045	(177)	4,090	(354)
Non-service component of retiree benefit costs	(5,366)	(3,759)	10,728	7,307
Net gain (loss) on financial instruments	11,697	(67,649)	10,812	(65,780)
Other Nonoperating Income (Expense)	6,013	(71,569)	(702)	(73,393)
EARNINGS (LOSS) FROM CONTINUING OPERATIONS BEFORE INCOME TAXES	29,911	(48,444)	50,839	(32,338)
INCOME TAX EXPENSE	(5,447)	(5,474)	10,693	11,784
EARNINGS (LOSS) FROM CONTINUING OPERATIONS	24,464	(53,918)	40,146	(44,122)
EARNINGS FROM DISCONTINUED OPERATIONS, NET OF TAXES	170	192	366	384
NET EARNINGS (LOSS)	$ 24,634	$ (53,726)	$ 40,512	$ (43,738)
BASIC EARNINGS (LOSS) PER SHARE
Basic earnings per share from continuing operations (in dollars per share)	$ 0.42	$ (0.91)	$ 0.68	$ (0.75)
Discontinued operations (in dollars per share)	0.00	0.00	0.01	0.01
TOTAL BASIC EARNINGS PER SHARE (in dollars per share)	0.42	(0.91)	0.69	(0.74)
DILUTED EARNINGS (LOSS) PER SHARE
Diluted earnings per share from continuing operations (in dollars per share)	0.21	(0.91)	0.48	(0.75)
Discontinued operations (in dollars per share)	0.00	0.00	0.00	0.01
TOTAL DILUTED NET EARNINGS PER SHARE (in dollars per share)	$ 0.21	$ (0.91)	$ 0.48	$ (0.74)
WEIGHTED AVERAGE SHARES
Basic (in shares)	58,739	59,035	58,790	59,084
Diluted (in shares)	68,363	59,035	68,784	59,084