Consolidated Statements of Cash Flows (Unaudited) (USD $)	9 Months Ended
	Jun. 30, 2012	Jun. 30, 2011
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income (loss)	$ 9,961,000	$ (6,190,000)
Adjustments to reconcile net income (loss) to net cash provided (used) by operating activities:
Depreciation	24,092,000	22,767,000
Noncash compensation	1,037,000	1,422,000
Deferred income tax expense	4,335,000	1,449,000
Provision for bad debts	325,000	213,000
Other	161,000	(631,000)
Change in current assets and liabilities:
Decrease (increase) in accounts receivable	30,374,000	(27,696,000)
Increase in prepaid expenses and other assets	(916,000)	(4,230,000)
(Decrease) increase in accounts payable	(3,945,000)	7,847,000
Decrease in accrued liabilities	(2,124,000)	(247,000)
(Decrease) increase in deferred revenue	(5,296,000)	4,827,000
Net cash provided (used) by operating activities	58,004,000	(469,000)
CASH FLOWS FROM INVESTING ACTIVITIES:
Capital expenditures, net of noncash capital expenditures summarized below in noncash investing and financing activities	(28,962,000)	(55,307,000)
Proceeds from maturity of short-term investments		22,500,000
Acquisition of short-term investments	(2,750,000)	(2,500,000)
Proceeds from disposal of assets	252,000	623,000
Partial proceeds on fire insurance claim		758,000
Net cash used in investing activities	(31,460,000)	(33,926,000)
CASH FLOWS FROM FINANCING ACTIVITIES:
Proceeds from note payable		16,427,000
Principal payments on note payable	(3,948,000)
Principal payments on capital lease obligations	(118,000)
Proceeds from exercise of stock options	184,000	297,000
Net cash (used) provided by financing activities	(3,882,000)	16,724,000
Net increase (decrease) in cash and cash equivalents	22,662,000	(17,671,000)
CASH AND CASH EQUIVALENTS AT BEGINNING OF PERIOD	26,077,000	29,675,000
CASH AND CASH EQUIVALENTS AT END OF PERIOD	48,739,000	12,004,000
SUPPLEMENTAL CASH FLOW INFORMATION:
Cash paid for interest expense	436,000
Cash paid for income taxes	262,000	508,000
Cash received for income taxes	137,000	202,000
NONCASH INVESTING AND FINANCING ACTIVITIES:
Accrued purchases of property and equipment	12,156,000	957,000
Capital lease obligations incurred	$ 1,427,000