Condensed Consolidating Financial Information - Balance Sheets (Details) - USD ($) $ in Thousands	Mar. 31, 2016	Sep. 30, 2015	Mar. 31, 2015	Sep. 30, 2014
Current assets:
Cash and cash equivalents	$ 58,491	$ 142,597	$ 79,723	$ 152,542
Trade receivables, net	106,152	134,384
Inventories	66,080	55,074
Current income taxes	2,430	329
Other	11,162	11,827
Total current assets	244,315	344,211
Property, plant and equipment, net	194,377	185,718
Other assets:
Goodwill	246,167	178,199
Intangible assets, net	161,762	143,718
Deferred income taxes	83,626	92,852
Other	40,407	34,321
Total other assets	531,962	449,090
Total assets	970,654	979,019	979,019
Current liabilities:
Accounts payable	20,017	25,306
Accrued personnel costs	35,389	52,544
Accrued interest	2,241	2,295
Other accrued liabilities	52,108	49,486
Current portion of long-term debt	4,250	4,250
Total current liabilities	114,005	133,881
Long-term liabilities:
Long-term debt, net	553,330	558,080
Income taxes	2,930	6,590
Other	34,260	30,186
Total long-term liabilities	590,520	594,856
Total liabilities	704,525	728,737
Redeemable non-controlling interest in consolidated subsidiary	12,275	12,431
Stockholders' equity:
Common stock	74	74
Capital in excess of par value	730,349	728,667
Retained earnings (accumulated deficit)	(475,363)	(489,889)
Treasury stock	(1,206)	(1,001)
Total stockholders' equity	253,854	237,851
Total liabilities and stockholders' equity	970,654	979,019
Consolidation, Eliminations
Current assets:
Current income taxes	(153,072)	(142,976)
Total current assets	(153,072)	(142,976)
Other assets:
Investments in subsidiaries	(441,624)	(428,708)
Intercompany accounts and notes	(719,136)	(694,839)
Deferred income taxes	(18,165)	(12,115)
Total other assets	(1,178,925)	(1,135,662)
Total assets	(1,331,997)	(1,278,638)
Current liabilities:
Current income taxes	(153,072)	(142,976)
Total current liabilities	(153,072)	(142,976)
Long-term liabilities:
Income taxes	(18,165)	(12,115)
Intercompany accounts and notes	(719,136)	(694,839)
Total long-term liabilities	(737,301)	(706,954)
Total liabilities	(890,373)	(849,930)
Stockholders' equity:
Capital in excess of par value	(523,984)	(540,715)
Retained earnings (accumulated deficit)	82,360	112,007
Total stockholders' equity	(441,624)	(428,708)
Total liabilities and stockholders' equity	(1,331,997)	(1,278,638)
Guarantor Subsidiaries
Current assets:
Cash and cash equivalents	15,989	25,819	36,633	33,552
Trade receivables, net	99,911	129,095
Inventories	62,367	52,699
Other	10,089	10,666
Total current assets	188,356	218,279
Property, plant and equipment, net	171,457	164,413
Other assets:
Goodwill	204,301	147,330
Intangible assets, net	124,403	116,479
Investments in subsidiaries		55,844
Intercompany accounts and notes	97,656	57,793
Other	12,937	11,243
Total other assets	439,297	388,689
Total assets	799,110	771,381
Current liabilities:
Accounts payable	18,568	23,619
Accrued personnel costs	11,604	14,542
Current income taxes	146,927	137,502
Other accrued liabilities	45,967	39,604
Total current liabilities	223,066	215,267
Long-term liabilities:
Income taxes	21,090	15,091
Other	1,033	1,481
Total long-term liabilities	22,123	16,572
Total liabilities	245,189	231,839
Stockholders' equity:
Capital in excess of par value	471,779	486,069
Retained earnings (accumulated deficit)	82,142	53,473
Total stockholders' equity	553,921	539,542
Total liabilities and stockholders' equity	799,110	771,381
Non-Guarantor Subsidiaries
Current assets:
Cash and cash equivalents	3,192	3,577	2,975	5,764
Trade receivables, net	6,241	5,289
Inventories	3,713	2,375
Other	266	144
Total current assets	13,412	11,385
Property, plant and equipment, net	10,179	9,978
Other assets:
Goodwill	41,866	30,869
Intangible assets, net	37,359	27,239
Deferred income taxes	25,045	25,204
Other	2,396	2,291
Total other assets	106,666	85,603
Total assets	130,257	106,966
Current liabilities:
Accounts payable	1,240	1,114
Accrued personnel costs	241	501
Current income taxes	6,145	5,474
Other accrued liabilities	3,778	6,380
Total current liabilities	11,404	13,469
Long-term liabilities:
Income taxes	5
Intercompany accounts and notes	202,476	178,179
Other	16,570	13,897
Total long-term liabilities	219,051	192,076
Total liabilities	230,455	205,545
Redeemable non-controlling interest in consolidated subsidiary	12,275	12,431
Stockholders' equity:
Capital in excess of par value	52,029	54,470
Retained earnings (accumulated deficit)	(164,502)	(165,480)
Total stockholders' equity	(112,473)	(111,010)
Total liabilities and stockholders' equity	130,257	106,966
Parent Company
Current assets:
Cash and cash equivalents	39,310	113,201	$ 40,115	$ 113,226
Current income taxes	155,502	143,305
Other	807	1,017
Total current assets	195,619	257,523
Property, plant and equipment, net	12,741	11,327
Other assets:
Investments in subsidiaries	441,624	372,864
Intercompany accounts and notes	621,480	637,046
Deferred income taxes	76,746	79,763
Other	25,074	20,787
Total other assets	1,164,924	1,110,460
Total assets	1,373,284	1,379,310
Current liabilities:
Accounts payable	209	573
Accrued personnel costs	23,544	37,501
Accrued interest	2,241	2,295
Other accrued liabilities	2,363	3,502
Current portion of long-term debt	4,250	4,250
Total current liabilities	32,607	48,121
Long-term liabilities:
Long-term debt, net	553,330	558,080
Income taxes		3,614
Intercompany accounts and notes	516,660	516,660
Other	16,657	14,808
Total long-term liabilities	1,086,647	1,093,162
Total liabilities	1,119,254	1,141,283
Stockholders' equity:
Common stock	74	74
Capital in excess of par value	730,525	728,843
Retained earnings (accumulated deficit)	(475,363)	(489,889)
Treasury stock	(1,206)	(1,001)
Total stockholders' equity	254,030	238,027
Total liabilities and stockholders' equity	$ 1,373,284	$ 1,379,310