CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	3 Months Ended	15 Months Ended
	Mar. 31, 2016	Mar. 31, 2017
Cash flows from operating activities:
Net income	$ 4,575	$ 4,872
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	3,700	3,906
Amortization of deferred loan costs	76	134
Stock-based compensation	127	962
Excess tax benefit from stock-based compensation	(70)
Provision for bad debts	18	48
Loss (gain) on disposition of assets	56	18
Changes in operating assets and liabilities:
Receivables	231	581
Inventories	43	193
Prepaid expenses	(294)	374
Accounts payable	1,253	(1,224)
Accrued expenses	(1,395)	(2,274)
Income taxes	2,441	2,720
Net cash provided by operating activities	10,761	10,310
Cash flows from investing activities:
Proceeds from sale of assets		1
Change in construction payable	466	90
Acquisition of property and equipment	(8,928)	(12,246)
Net cash used in investing activities	(8,462)	(12,155)
Cash flows from financing activities:
Net exercise of stock options	376
Excess tax benefit from stock-based compensation	70
Principal payments on long-term debt	(5,500)
Net cash used in financing activities	(5,054)
Net increase (decrease) in cash	(2,755)	(1,845)
Cash and cash equivalents at beginning of period	21,164	21,164
Cash and cash equivalents at end of period	18,409	24,538
Supplemental disclosure of cash flow information
Cash paid for interest, net of amounts capitalized	$ 9	$ 138