Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Operating Activities:
Net income	$ 28,111	$ 22,259
Noncash items included in net income:
Depreciation and amortization	32,590	26,782
Deferred income taxes	7,069	5,315
Other, net	2,129	2,761
Changes in operating assets and liabilities, net	(18,632)	(26,717)
Net cash provided by operating activities	51,267	30,400
Investing Activities:
Acquisition of property and equipment	(107,591)	(56,741)
Proceeds from disposal of property and equipment	4,915	275
Net cash used in investing activities	(102,676)	(56,466)
Financing Activities:
Repayment of revolving credit agreement	(86,734)	(55,780)
Borrowing of revolving credit agreement	190,874	86,388
Proceeds from stock option exercises	2,137	1,798
Shares withheld for taxes	(3,404)	(3,268)
Debt issuance costs		(646)
Repayment of finance leases	(4,803)	(4,589)
Net cash provided by financing activities	98,070	23,903
Net Increase (Decrease) in Cash and Cash Equivalents	46,661	(2,163)
Cash and cash equivalents, beginning of period	248	2,194
Cash and cash equivalents, end of period	$ 46,909	$ 31