Condensed Consolidating Financial Information - Statements of Cash Flows (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Cash flows from operating activities:
Net income	$ 17,785	$ 23,008	$ 32,890	$ 4,894
Adjustments to reconcile net income to net cash provided by (used in) operating activities:
Depreciation and amortization	15,156	13,937	43,053	39,793
Interest expense related to amortization of debt issue costs and debt discount	600	600	1,745	5,611
Stock-based compensation	800	700	2,337	2,069
Deferred income taxes			17,629	954
Tax benefit from exercise of stock appreciation rights and vesting of restricted stock			(332)	0
Net loss (gain) on disposition of property, plant and equipment			(1,631)	95
Loss on sale of discontinued operations, net of income taxes			3,072	219
Net loss of unconsolidated joint ventures			36	247
Equity in earnings of subsidiaries			0	0
Decrease (increase) in trade receivables			4,579	506
Increase in inventories			(1,879)	(8,927)
Increase (decrease) in accounts payable and accrued liabilities			(18,062)	(29,479)
Other changes in operating assets and liabilities, net			(4,030)	(10,788)
Net cash provided by (used in) operating activities			79,407	5,194
Cash flows from investing activities:
Business acquisitions			(106,924)	(1,200)
Investments in unconsolidated joint ventures			0	(125)
Purchase of property, plant and equipment	(10,537)	(9,050)	(31,419)	(26,524)
Proceeds from disposition of property, plant and equipment			8,795	716
Net decrease (increase) in long-term receivables and deposits			(200)	3,847
Net change in other assets			1,869	(423)
Net cash used in investing activities			(127,879)	(23,709)
Cash flows from financing activities:
Net proceeds from issuance of long-term debt			0	414,675
Payments on long-term debt			(6,937)	(448,736)
Dividends paid to non-controlling interest in consolidated subsidiary			(735)	(1,184)
Employee stock purchases			718	633
Tax benefit from exercise of stock appreciation rights and vesting of restricted stock			332	0
Intercompany transfers			0	0
Net cash provided by (used in) financing activities			(6,622)	(34,612)
Net increase (decrease) in cash and cash equivalents			(55,094)	(53,127)
Cash and cash equivalents, beginning of period			142,597	152,542
Cash and cash equivalents, end of period	87,503	99,415	87,503	99,415
Consolidation, Eliminations
Cash flows from operating activities:
Net income	(27,113)	(34,508)	(56,760)	(68,633)
Adjustments to reconcile net income to net cash provided by (used in) operating activities:
Equity in earnings of subsidiaries	27,113	34,508	56,760	68,633
Guarantor Subsidiaries
Cash flows from operating activities:
Net income	25,990	33,752	54,763	66,077
Adjustments to reconcile net income to net cash provided by (used in) operating activities:
Depreciation and amortization			40,297	37,270
Stock-based compensation			817	759
Deferred income taxes			4,927	591
Tax benefit from exercise of stock appreciation rights and vesting of restricted stock			(106)
Net loss (gain) on disposition of property, plant and equipment			(1,680)	94
Loss on sale of discontinued operations, net of income taxes				45
Decrease (increase) in trade receivables			5,948	397
Increase in inventories			(1,709)	(8,513)
Increase (decrease) in accounts payable and accrued liabilities			(16,370)	(10,650)
Other changes in operating assets and liabilities, net			(29,513)	(339)
Net cash provided by (used in) operating activities			57,374	85,731
Cash flows from investing activities:
Business acquisitions			(73,841)	(1,200)
Investments in unconsolidated joint ventures				(125)
Purchase of property, plant and equipment			(28,596)	(21,768)
Proceeds from disposition of property, plant and equipment			8,795	716
Net decrease (increase) in long-term receivables and deposits			2	2,781
Net change in other assets			(1,526)	(587)
Net cash used in investing activities			(95,166)	(20,183)
Cash flows from financing activities:
Employee stock purchases			509	464
Tax benefit from exercise of stock appreciation rights and vesting of restricted stock			106
Intercompany transfers			35,982	(41,029)
Net cash provided by (used in) financing activities			36,597	(40,565)
Net increase (decrease) in cash and cash equivalents			(1,195)	24,983
Cash and cash equivalents, beginning of period			25,819	33,552
Cash and cash equivalents, end of period	24,624	58,535	24,624	58,535
Non-Guarantor Subsidiaries
Cash flows from operating activities:
Net income	1,392	947	2,845	3,251
Adjustments to reconcile net income to net cash provided by (used in) operating activities:
Depreciation and amortization			2,269	2,153
Deferred income taxes			(284)	363
Net loss (gain) on disposition of property, plant and equipment			49	1
Loss on sale of discontinued operations, net of income taxes			3,072	174
Net loss of unconsolidated joint ventures			36	247
Decrease (increase) in trade receivables			(1,369)	109
Increase in inventories			(170)	(414)
Increase (decrease) in accounts payable and accrued liabilities			5,183	3,231
Other changes in operating assets and liabilities, net			(5,128)	(8,519)
Net cash provided by (used in) operating activities			6,503	596
Cash flows from investing activities:
Business acquisitions			(33,083)
Purchase of property, plant and equipment			(355)	(614)
Net decrease (increase) in long-term receivables and deposits			(55)
Net change in other assets			6,085
Net cash used in investing activities			(27,408)	(614)
Cash flows from financing activities:
Dividends paid to non-controlling interest in consolidated subsidiary			(735)	(1,184)
Employee stock purchases			31	28
Intercompany transfers			27,853	(271)
Net cash provided by (used in) financing activities			27,149	(1,427)
Net increase (decrease) in cash and cash equivalents			6,244	(1,445)
Cash and cash equivalents, beginning of period			3,577	5,764
Cash and cash equivalents, end of period	9,821	4,319	9,821	4,319
Parent Company
Cash flows from operating activities:
Net income	17,516	22,817	32,042	4,199
Adjustments to reconcile net income to net cash provided by (used in) operating activities:
Depreciation and amortization			487	370
Interest expense related to amortization of debt issue costs and debt discount			1,745	5,611
Stock-based compensation			1,520	1,310
Deferred income taxes			12,986
Tax benefit from exercise of stock appreciation rights and vesting of restricted stock			(226)
Equity in earnings of subsidiaries	(27,113)	(34,508)	(56,760)	(68,633)
Increase (decrease) in accounts payable and accrued liabilities			(6,875)	(22,060)
Other changes in operating assets and liabilities, net			30,611	(1,930)
Net cash provided by (used in) operating activities			15,530	(81,133)
Cash flows from investing activities:
Purchase of property, plant and equipment			(2,468)	(4,142)
Net decrease (increase) in long-term receivables and deposits			(147)	1,066
Net change in other assets			(2,690)	164
Net cash used in investing activities			(5,305)	(2,912)
Cash flows from financing activities:
Net proceeds from issuance of long-term debt				414,675
Payments on long-term debt			(6,937)	(448,736)
Employee stock purchases			178	141
Tax benefit from exercise of stock appreciation rights and vesting of restricted stock			226
Intercompany transfers			(63,835)	41,300
Net cash provided by (used in) financing activities			(70,368)	7,380
Net increase (decrease) in cash and cash equivalents			(60,143)	(76,665)
Cash and cash equivalents, beginning of period			113,201	113,226
Cash and cash equivalents, end of period	$ 53,058	$ 36,561	$ 53,058	$ 36,561