Condensed Consolidating Financial Information - Statements of Cash Flows (Details) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Sep. 30, 2016
Cash flows from operating activities:
Net income	$ 6,828	$ 12,721
Adjustments to reconcile net income to net cash provided by (used in) operating activities:
Depreciation and amortization	17,842	13,782
Interest expense related to amortization of debt issue costs and debt discount	930	567
Stock-based compensation	485	708
Deferred income taxes	3,910	6,482
Tax benefit from exercise of stock appreciation rights and vesting of restricted stock	(5,257)	(64)
Net loss (gain) on disposition of property, plant and equipment	(114)	(47)
Net loss of unconsolidated joint venture	12	13
Equity in earnings of subsidiaries	0
Decrease (increase) in trade receivables	33,812	43,521
Increase in inventories	(8,127)	(1,259)
Decrease in accounts payable and accrued liabilities	(21,139)	(34,434)
Other changes in operating assets and liabilities, net	(1,521)	(423)
Net cash provided by (used in) operating activities	27,661	41,567
Cash flows from investing activities:
Business acquisitions	0	(57,301)
Purchase of property, plant and equipment	(15,540)	(7,685)
Proceeds from disposition of property, plant and equipment	162	95
Net decrease (increase) in long-term receivables and deposits	851	(1,301)
Net change in other assets	1,832	(1,357)
Net cash provided by (used in) investing activities	(12,695)	(67,549)
Cash flows from financing activities:
Payments on long-term debt	(15,000)	(1,062)
Dividends paid to non-controlling interest in consolidated subsidiary	0	(355)
Employee stock purchases	337	374
Tax benefit from exercise of stock appreciation rights and vesting of restricted stock	5,257	64
Intercompany transfers	0	0
Net cash provided by (used in) financing activities	(9,406)	(979)
Net increase (decrease) in cash and cash equivalents	5,560	(26,961)
Cash and cash equivalents, beginning of period	65,298	142,597	$ 142,597
Cash and cash equivalents, end of period	70,858	115,636	65,298
Consolidation, Eliminations
Cash flows from operating activities:
Net income	(17,565)	(18,626)
Adjustments to reconcile net income to net cash provided by (used in) operating activities:
Equity in earnings of subsidiaries	17,565	18,626
Guarantor Subsidiaries
Cash flows from operating activities:
Net income	17,324	18,191
Adjustments to reconcile net income to net cash provided by (used in) operating activities:
Depreciation and amortization	15,809	12,877
Stock-based compensation	188	259
Tax benefit from exercise of stock appreciation rights and vesting of restricted stock		(63)
Net loss (gain) on disposition of property, plant and equipment	(117)	(49)
Decrease (increase) in trade receivables	34,137	43,227
Increase in inventories	(7,972)	(889)
Decrease in accounts payable and accrued liabilities	(10,350)	(20,444)
Other changes in operating assets and liabilities, net	(10,388)	2,153
Net cash provided by (used in) operating activities	38,631	55,262
Cash flows from investing activities:
Business acquisitions		(34,602)
Purchase of property, plant and equipment	(14,470)	(6,727)
Proceeds from disposition of property, plant and equipment	137	107
Net decrease (increase) in long-term receivables and deposits	901	(1,178)
Net change in other assets	(308)	(78)
Net cash provided by (used in) investing activities	(13,740)	(42,478)
Cash flows from financing activities:
Employee stock purchases	235	275
Tax benefit from exercise of stock appreciation rights and vesting of restricted stock		63
Intercompany transfers	(24,570)	(10,578)
Net cash provided by (used in) financing activities	(24,335)	(10,240)
Net increase (decrease) in cash and cash equivalents	556	2,544
Cash and cash equivalents, beginning of period	27,012	25,819	25,819
Cash and cash equivalents, end of period	27,568	28,363	27,012
Non-Guarantor Subsidiaries
Cash flows from operating activities:
Net income	402	731
Adjustments to reconcile net income to net cash provided by (used in) operating activities:
Depreciation and amortization	1,326	746
Deferred income taxes	90
Net loss (gain) on disposition of property, plant and equipment	3	2
Net loss of unconsolidated joint venture	12	13
Decrease (increase) in trade receivables	(325)	294
Increase in inventories	(155)	(370)
Decrease in accounts payable and accrued liabilities	(436)	(735)
Other changes in operating assets and liabilities, net	606	205
Net cash provided by (used in) operating activities	1,523	886
Cash flows from investing activities:
Business acquisitions		(22,699)
Purchase of property, plant and equipment	(228)	(56)
Proceeds from disposition of property, plant and equipment	25	(12)
Net decrease (increase) in long-term receivables and deposits	3
Net change in other assets	(14)	(38)
Net cash provided by (used in) investing activities	(214)	(22,805)
Cash flows from financing activities:
Dividends paid to non-controlling interest in consolidated subsidiary		(355)
Employee stock purchases	27	11
Intercompany transfers	1,021	22,401
Net cash provided by (used in) financing activities	1,048	22,057
Net increase (decrease) in cash and cash equivalents	2,357	138
Cash and cash equivalents, beginning of period	5,304	3,577	3,577
Cash and cash equivalents, end of period	7,661	3,715	5,304
Parent
Cash flows from operating activities:
Net income	6,667	12,425
Adjustments to reconcile net income to net cash provided by (used in) operating activities:
Depreciation and amortization	707	159
Interest expense related to amortization of debt issue costs and debt discount	930	567
Stock-based compensation	297	449
Deferred income taxes	3,820	6,482
Tax benefit from exercise of stock appreciation rights and vesting of restricted stock	(5,257)	(1)
Equity in earnings of subsidiaries	(17,565)	(18,626)
Decrease in accounts payable and accrued liabilities	(10,353)	(13,255)
Other changes in operating assets and liabilities, net	8,261	(2,781)
Net cash provided by (used in) operating activities	(12,493)	(14,581)
Cash flows from investing activities:
Purchase of property, plant and equipment	(842)	(902)
Net decrease (increase) in long-term receivables and deposits	(53)	(123)
Net change in other assets	2,154	(1,241)
Net cash provided by (used in) investing activities	1,259	(2,266)
Cash flows from financing activities:
Payments on long-term debt	(15,000)	(1,062)
Employee stock purchases	75	88
Tax benefit from exercise of stock appreciation rights and vesting of restricted stock	5,257	1
Intercompany transfers	23,549	(11,823)
Net cash provided by (used in) financing activities	13,881	(12,796)
Net increase (decrease) in cash and cash equivalents	2,647	(29,643)
Cash and cash equivalents, beginning of period	32,982	113,201	113,201
Cash and cash equivalents, end of period	$ 35,629	$ 83,558	$ 32,982