Condensed Consolidating Financial Information (Details 4) (USD $) In Thousands, unless otherwise specified	3 Months Ended								12 Months Ended
	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2012
Cash flows from operating activities:
Net income (loss)	$ 16,681	$ 10,893	$ (10,082)	$ (1,434)	$ 10,253	$ 11,016	$ (8,260)	$ (5,872)	$ 16,058	$ 7,137	$ (62,248)
Adjustments to reconcile net income (loss) to net cash provided by (used in) operating activities:
Depreciation and amortization									55,134	52,317	51,481
Interest expense related to amortization of debt issue costs and debt discount									2,175	5,841	14,184
Stock-based compensation									2,165	1,703	1,737
Deferred income taxes									1,666	698	198
Net loss (gain) on disposition of property, plant and equipment									95	(649)	(538)
Loss (gain) on sale of discontinued operations, net of income taxes									(2,727)	55	(267)
Asset impairments									1,815	0	13,166
Net loss of unconsolidated joint ventures									529	0	9,314
Gain on convertible debt repayments									0	(35)	(2,479)
Equity in earnings of subsidiaries									0	0	0
Decrease (increase) in trade receivables									517	(5,035)	(9,792)
Decrease (increase) in inventories									(2,347)	2,221	2,954
Increase (decrease) in accounts payable and accrued liabilities									(13,225)	(4,218)	27,443
Other changes in operating assets and liabilities, net									(1,478)	(1,472)	1,016
Net cash provided by (used in) operating activities									60,377	58,563	46,169
Cash flows from investing activities:
Business acquisitions									(94,998)	(43,250)	(996)
Investments in unconsolidated joint ventures									(1,875)	0	0
Proceeds from sale of investments in unconsolidated joint ventures									0	0	18,522
Purchase of property, plant and equipment									(35,799)	(29,119)	(26,447)
Proceeds from disposition of property, plant and equipment									905	791	1,261
Proceeds from sale of discontinued operations									4,666	4,813	2,000
Net decrease (increase) in long-term receivables and deposits									7,445	(1,171)	(42)
Net change in other assets									(2,162)	(437)	(706)
Net cash used in investing activities									(121,818)	(68,373)	(6,408)
Cash flows from financing activities:
Net proceeds from issuance of long-term debt									146,650	0	0
Net proceeds from issuance of common stock									0	77,957	0
Payments on long-term debt									(7,792)	(47,355)	(36,334)
Dividends paid to non-controlling interest in consolidated subsidiary									(950)	0	0
Debt issue costs									0	0	(1,090)
Employee stock purchases									759	742	635
Intercompany transfers									0	0	0
Net cash provided by (used in) financing activities									138,667	31,344	(36,789)
Net increase (decrease) in cash and cash equivalents									77,226	21,534	2,972
Cash and cash equivalents, beginning of year				75,316				53,782	75,316	53,782	50,810
Cash and cash equivalents, end of year	152,542				75,316				152,542	75,316	53,782
Consolidation, Eliminations
Cash flows from operating activities:
Net income (loss)									(62,719)	(47,117)	13,536
Adjustments to reconcile net income (loss) to net cash provided by (used in) operating activities:
Equity in earnings of subsidiaries									62,719	47,117	(13,536)
Guarantor Subsidiaries | Reportable Legal Entities
Cash flows from operating activities:
Net income (loss)									60,141	47,117	(13,536)
Adjustments to reconcile net income (loss) to net cash provided by (used in) operating activities:
Depreciation and amortization									52,716	52,027	51,333
Stock-based compensation									843	765	673
Deferred income taxes									1,062	698	199
Net loss (gain) on disposition of property, plant and equipment									44	(649)	(538)
Loss (gain) on sale of discontinued operations, net of income taxes									(2,727)	55	(267)
Asset impairments									1,815		13,166
Net loss of unconsolidated joint ventures											9,314
Decrease (increase) in trade receivables									(90)	(5,035)	(9,792)
Decrease (increase) in inventories									(3,927)	2,221	2,954
Increase (decrease) in accounts payable and accrued liabilities									(17,364)	(5,637)	9,646
Other changes in operating assets and liabilities, net									33,349	31,000	16,928
Net cash provided by (used in) operating activities									125,862	122,562	80,080
Cash flows from investing activities:
Business acquisitions									(10,500)	(43,250)	(996)
Proceeds from sale of investments in unconsolidated joint ventures											18,522
Purchase of property, plant and equipment									(30,672)	(26,940)	(24,419)
Proceeds from disposition of property, plant and equipment									905	791	1,261
Proceeds from sale of discontinued operations									4,666	4,813	2,000
Net decrease (increase) in long-term receivables and deposits									7,145	(1,890)	24
Net change in other assets									(2,275)	(294)	(214)
Net cash used in investing activities									(30,731)	(66,770)	(3,822)
Cash flows from financing activities:
Employee stock purchases									580	539	462
Intercompany transfers									(132,872)	(29,695)	(68,731)
Net cash provided by (used in) financing activities									(132,292)	(29,156)	(68,269)
Net increase (decrease) in cash and cash equivalents									(37,161)	26,636	7,989
Cash and cash equivalents, beginning of year				70,747				44,111	70,747	44,111	36,122
Cash and cash equivalents, beginning of year				70,713					70,713
Cash and cash equivalents, end of year	33,552				70,747				33,552	70,747	44,111
Cash and cash equivalents, end of year					70,713					70,713
Non-Guarantor Subsidiaries | Reportable Legal Entities
Cash flows from operating activities:
Net income (loss)									3,352
Adjustments to reconcile net income (loss) to net cash provided by (used in) operating activities:
Depreciation and amortization									2,146
Deferred income taxes									604
Net loss (gain) on disposition of property, plant and equipment									6
Net loss of unconsolidated joint ventures									529
Decrease (increase) in trade receivables									607
Decrease (increase) in inventories									1,580
Increase (decrease) in accounts payable and accrued liabilities									828
Other changes in operating assets and liabilities, net									129
Net cash provided by (used in) operating activities									9,781
Cash flows from investing activities:
Investments in unconsolidated joint ventures									(1,875)
Purchase of property, plant and equipment									(829)
Net cash used in investing activities									(2,704)
Cash flows from financing activities:
Dividends paid to non-controlling interest in consolidated subsidiary									(950)
Intercompany transfers									(397)
Net cash provided by (used in) financing activities									(1,347)
Net increase (decrease) in cash and cash equivalents									5,730
Cash and cash equivalents, beginning of year				34					34
Cash and cash equivalents, end of year	5,764								5,764
Parent Company | Reportable Legal Entities
Cash flows from operating activities:
Net income (loss)									15,284	7,137	(62,248)
Adjustments to reconcile net income (loss) to net cash provided by (used in) operating activities:
Depreciation and amortization									272	290	148
Interest expense related to amortization of debt issue costs and debt discount									2,175	5,841	14,184
Stock-based compensation									1,322	938	1,064
Deferred income taxes											(1)
Net loss (gain) on disposition of property, plant and equipment									45
Gain on convertible debt repayments										(35)	(2,479)
Equity in earnings of subsidiaries									(62,719)	(47,117)	13,536
Increase (decrease) in accounts payable and accrued liabilities									3,311	1,419	17,797
Other changes in operating assets and liabilities, net									(34,956)	(32,472)	(15,912)
Net cash provided by (used in) operating activities									(75,266)	(63,999)	(33,911)
Cash flows from investing activities:
Business acquisitions									(84,498)
Purchase of property, plant and equipment									(4,298)	(2,179)	(2,028)
Net decrease (increase) in long-term receivables and deposits									300	719	(66)
Net change in other assets									113	(143)	(492)
Net cash used in investing activities									(88,383)	(1,603)	(2,586)
Cash flows from financing activities:
Net proceeds from issuance of long-term debt									146,650
Net proceeds from issuance of common stock										77,957
Payments on long-term debt									(7,792)	(47,355)	(36,334)
Debt issue costs											(1,090)
Employee stock purchases									179	203	173
Intercompany transfers									133,269	29,695	68,731
Net cash provided by (used in) financing activities									272,306	60,500	31,480
Net increase (decrease) in cash and cash equivalents									108,657	(5,102)	(5,017)
Cash and cash equivalents, beginning of year				4,569				9,671	4,569	9,671	14,688
Cash and cash equivalents, end of year	$ 113,226				$ 4,569				$ 113,226	$ 4,569	$ 9,671