CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015
Cash flows from operating activities:
Net income	$ 18,104	$ 15,536
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	11,134	12,157
Amortization of deferred loan costs	275	229
Stock-based compensation	983	938
Excess tax benefit from stock-based compensation	(425)	(286)
Provision for bad debts	92	80
Loss (gain) on disposition of assets	668	(20)
Changes in operating assets and liabilities:
Receivables	(981)	(703)
Inventories	74	158
Prepaid expenses	(879)	(684)
Accounts payable	611	201
Accrued expenses	(575)	665
Income taxes	94	160
Net cash provided by operating activities	29,175	28,431
Cash flows from investing activities:
Proceeds from sale of assets	16	23
Change in construction payable	(194)	1,903
Acquisition of property and equipment	(19,646)	(26,575)
Net cash used in investing activities	(19,824)	(24,649)
Cash flows from financing activities:
Net exercise of stock options	2,100	1,986
Excess tax benefit from stock-based compensation	425	286
Principal payments on long-term debt	(11,000)	(8,400)
Loan issuance cost	(2,586)
Net cash used in financing activities	(11,061)	(6,128)
Net decrease in cash	(1,710)	(2,346)
Cash and cash equivalents at beginning of period	21,164	21,583
Cash and cash equivalents at end of period	19,454	19,237
Supplemental disclosure of cash flow information
Cash paid for interest, net of amounts capitalized		308
Cash paid for income taxes	$ 9,475	$ 8,050