Condensed Consolidating Financial Information - Statements of Cash Flows (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Mar. 31, 2016	Mar. 31, 2015	Mar. 31, 2016	Mar. 31, 2015
Cash flows from operating activities:
Net income (loss)	$ 2,384	$ (25,198)	$ 15,105	$ (18,114)
Adjustments to reconcile net income (loss) to net cash provided by (used in) operating activities:
Depreciation and amortization	14,115	12,946	27,897	25,856
Interest expense related to amortization of debt issue costs and debt discount	600	4,500	1,184	5,042
Stock-based compensation	800	700	1,521	1,339
Deferred income taxes			8,643	477
Tax benefit from exercise of stock appreciation rights and vesting of restricted stock			(97)	0
Net loss (gain) on disposition of property, plant and equipment			(46)	113
Loss on sale of discontinued operations, net of income taxes			3,040	241
Net loss of unconsolidated joint ventures			26	234
Equity in earnings of subsidiaries			0	0
Decrease (increase) in trade receivables			33,538	28,347
Increase in inventories			(4,066)	(10,628)
Increase (decrease) in accounts payable and accrued liabilities			(36,372)	(47,580)
Other changes in operating assets and liabilities, net			(6,025)	(8,769)
Net cash provided by (used in) operating activities			44,348	(23,442)
Cash flows from investing activities:
Business acquisitions			(96,457)	(1,200)
Investments in unconsolidated joint ventures			0	(125)
Purchase of property, plant and equipment	(13,197)	(8,703)	(20,882)	(17,474)
Proceeds from disposition of property, plant and equipment			404	640
Net decrease (increase) in long-term receivables and deposits			(1,729)	3,650
Net change in other assets			(3,817)	(344)
Net cash used in investing activities			(122,481)	(14,853)
Cash flows from financing activities:
Net proceeds from issuance of long-term debt			0	414,675
Payments on long-term debt			(5,874)	(448,736)
Dividends paid to non-controlling interest in consolidated subsidiary			(735)	(927)
Employee stock purchases			539	464
Tax benefit from exercise of stock appreciation rights and vesting of restricted stock			97	0
Intercompany transfers			0	0
Net cash provided by (used in) financing activities			(5,973)	(34,524)
Net increase (decrease) in cash and cash equivalents			(84,106)	(72,819)
Cash and cash equivalents, beginning of period			142,597	152,542
Cash and cash equivalents, end of period	58,491	79,723	58,491	79,723
Consolidation, Eliminations
Cash flows from operating activities:
Net income (loss)	(11,021)	(12,325)	(29,647)	(34,125)
Adjustments to reconcile net income (loss) to net cash provided by (used in) operating activities:
Equity in earnings of subsidiaries	11,021	12,325	29,647	34,125
Guarantor Subsidiaries
Cash flows from operating activities:
Net income (loss)	10,582	11,486	28,773	32,325
Adjustments to reconcile net income (loss) to net cash provided by (used in) operating activities:
Depreciation and amortization			26,084	24,223
Stock-based compensation			537	496
Deferred income taxes			6,809	295
Tax benefit from exercise of stock appreciation rights and vesting of restricted stock			(95)
Net loss (gain) on disposition of property, plant and equipment			(49)	112
Loss on sale of discontinued operations, net of income taxes				45
Decrease (increase) in trade receivables			34,198	28,597
Increase in inventories			(3,097)	(10,071)
Increase (decrease) in accounts payable and accrued liabilities			(17,680)	(23,170)
Other changes in operating assets and liabilities, net			(9,522)	2,554
Net cash provided by (used in) operating activities			65,958	55,406
Cash flows from investing activities:
Business acquisitions			(73,800)	(1,200)
Investments in unconsolidated joint ventures				(125)
Purchase of property, plant and equipment			(18,856)	(14,496)
Proceeds from disposition of property, plant and equipment			404	640
Net decrease (increase) in long-term receivables and deposits			(1,546)	2,584
Net change in other assets			(1,443)	(437)
Net cash used in investing activities			(95,241)	(13,034)
Cash flows from financing activities:
Employee stock purchases			390	342
Tax benefit from exercise of stock appreciation rights and vesting of restricted stock			95
Intercompany transfers			18,968	(39,633)
Net cash provided by (used in) financing activities			19,453	(39,291)
Net increase (decrease) in cash and cash equivalents			(9,830)	3,081
Cash and cash equivalents, beginning of period			25,819	33,552
Cash and cash equivalents, end of period	15,989	36,633	15,989	36,633
Non-Guarantor Subsidiaries
Cash flows from operating activities:
Net income (loss)	722	1,098	1,453	2,304
Adjustments to reconcile net income (loss) to net cash provided by (used in) operating activities:
Depreciation and amortization			1,503	1,421
Deferred income taxes			159	182
Net loss (gain) on disposition of property, plant and equipment			3	1
Loss on sale of discontinued operations, net of income taxes			3,040	196
Net loss of unconsolidated joint ventures			26	234
Decrease (increase) in trade receivables			(660)	(250)
Increase in inventories			(969)	(557)
Increase (decrease) in accounts payable and accrued liabilities			(3,178)	2,248
Other changes in operating assets and liabilities, net			69	(7,521)
Net cash provided by (used in) operating activities			1,446	(1,742)
Cash flows from investing activities:
Business acquisitions			(22,657)
Purchase of property, plant and equipment			(268)	(259)
Net decrease (increase) in long-term receivables and deposits			(22)
Net change in other assets			(109)
Net cash used in investing activities			(23,056)	(259)
Cash flows from financing activities:
Dividends paid to non-controlling interest in consolidated subsidiary			(735)	(927)
Employee stock purchases			20	16
Intercompany transfers			21,940	123
Net cash provided by (used in) financing activities			21,225	(788)
Net increase (decrease) in cash and cash equivalents			(385)	(2,789)
Cash and cash equivalents, beginning of period			3,577	5,764
Cash and cash equivalents, end of period	3,192	2,975	3,192	2,975
Parent Company
Cash flows from operating activities:
Net income (loss)	2,101	(25,457)	14,526	(18,618)
Adjustments to reconcile net income (loss) to net cash provided by (used in) operating activities:
Depreciation and amortization			310	212
Interest expense related to amortization of debt issue costs and debt discount			1,184	5,042
Stock-based compensation			984	843
Deferred income taxes			1,675
Tax benefit from exercise of stock appreciation rights and vesting of restricted stock			(2)
Equity in earnings of subsidiaries	(11,021)	(12,325)	(29,647)	(34,125)
Increase (decrease) in accounts payable and accrued liabilities			(15,514)	(26,658)
Other changes in operating assets and liabilities, net			3,428	(3,802)
Net cash provided by (used in) operating activities			(23,056)	(77,106)
Cash flows from investing activities:
Purchase of property, plant and equipment			(1,758)	(2,719)
Net decrease (increase) in long-term receivables and deposits			(161)	1,066
Net change in other assets			(2,265)	93
Net cash used in investing activities			(4,184)	(1,560)
Cash flows from financing activities:
Net proceeds from issuance of long-term debt				414,675
Payments on long-term debt			(5,874)	(448,736)
Employee stock purchases			129	106
Tax benefit from exercise of stock appreciation rights and vesting of restricted stock			2
Intercompany transfers			(40,908)	39,510
Net cash provided by (used in) financing activities			(46,651)	5,555
Net increase (decrease) in cash and cash equivalents			(73,891)	(73,111)
Cash and cash equivalents, beginning of period			113,201	113,226
Cash and cash equivalents, end of period	$ 39,310	$ 40,115	$ 39,310	$ 40,115