Consolidated Statements of Operations - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
REVENUES	$ 440,916	$ 445,684
EXPENSES:
Operating	319,151	315,303
General and administrative	24,971	24,826
Depreciation and amortization	38,089	36,257
Asset impairments		259
Costs and Expenses, Total	382,211	376,645
OPERATING INCOME	58,705	69,039
OTHER (INCOME) EXPENSE:
Interest expense, net	19,036	16,490
Other (income) expense	(43)	17
Total non-operating expense (income)	18,993	16,507
INCOME BEFORE INCOME TAXES	39,712	52,532
Income tax expense	(1,935)	(2,485)
NET INCOME	$ 37,777	$ 50,047
BASIC EARNINGS PER SHARE	$ 0.32	$ 0.42
DILUTED EARNINGS PER SHARE	0.32	0.42
DIVIDENDS DECLARED PER SHARE	$ 0.43	$ 0.42