Condensed Consolidated Statements of Operations and Comprehensive Income (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Revenues	$ 265,761	$ 207,434
Costs and expenses
Operating (excluding depreciation and amortization)	94,739	69,083
Selling, general and administrative	50,949	46,385
Depreciation and amortization	48,778	39,536
(Gain) loss on disposal of assets, net	6,634	(6,146)
Total costs and expenses	201,100	148,858
Income from operations	64,661	58,576
Interest expense	(14,723)	(7,606)
Other income (expense), net	617	287
Income before income taxes	50,555	51,257
Income tax provision	9,902	19,144
Net income	$ 40,653	$ 32,113
Net income per common share:
Basic (in dollars per share)	$ 7.13	$ 5.66
Diluted (in dollars per share)	$ 7.08	$ 5.60
Weighted average common shares outstanding:
Basic (in shares)	5,702,539	5,671,838
Diluted (in shares)	5,742,648	5,730,901
Other comprehensive gain (loss), net of tax	$ 1	$ 2
Comprehensive income	$ 40,654	$ 32,115
Dividends declared per common share (in dollars per share)	$ 1.75	$ 1.50