Fair Value of Financial Instruments (Details) - USD ($) $ in Thousands					1 Months Ended	3 Months Ended		6 Months Ended	12 Months Ended
	Feb. 02, 2016	Dec. 21, 2015	Nov. 04, 2015	Dec. 16, 2014	Dec. 31, 2015	Mar. 31, 2016	Dec. 31, 2015	Mar. 31, 2016	Sep. 30, 2015
Assets and liabilities measured at fair value on a recurring basis
Contingent consideration payments related to acquisitions of businesses								$ (1,679)
DTECH
Assets and liabilities measured at fair value on a recurring basis
Volatility earning metrics								22.00%	20.00%
Initial measurement recognized at acquisition				$ 99,400
Cash paid to seller					$ (5,000)
H4 Global
Assets and liabilities measured at fair value on a recurring basis
Contingent consideration paid based upon contracts entered period			5 years
Initial measurement recognized at acquisition			$ 1,900
TeraLogics
Assets and liabilities measured at fair value on a recurring basis
Volatility earning metrics								18.00%
Initial measurement recognized at acquisition		$ 9,000
GATR
Assets and liabilities measured at fair value on a recurring basis
Volatility earning metrics								19.00%
Contingent consideration paid based upon contracts entered period	12 months
Level 2
Debt instruments
Fair Value						$ 206,600		$ 206,600	$ 125,800
Carrying value						201,400		201,400	126,700
Level 3
Assets and liabilities measured at fair value on a recurring basis
Balance at the Beginning period						10,018	$ 7,507	7,507
Initial measurement recognized at acquisition						2,500	6,702
Cash paid to seller							(5,000)
Adjustment to the provisional acquisition date valuation						(716)
Total remeasurement recognized in earnings						897	809
Balance at the ending period					10,018	12,699	10,018	12,699	7,507
Level 3 | DTECH
Assets and liabilities measured at fair value on a recurring basis
Balance at the Beginning period						3,316	7,507	7,507
Cash paid to seller							(5,000)
Total remeasurement recognized in earnings						1,084	809
Balance at the ending period					3,316	4,400	3,316	4,400	7,507
Level 3 | H4 Global
Assets and liabilities measured at fair value on a recurring basis
Balance at the Beginning period						1,602
Initial measurement recognized at acquisition							1,602
Adjustment to the provisional acquisition date valuation						(616)
Total remeasurement recognized in earnings						(187)
Balance at the ending period					1,602	799	1,602	799
Level 3 | GATR
Assets and liabilities measured at fair value on a recurring basis
Initial measurement recognized at acquisition						2,500
Total remeasurement recognized in earnings						100
Balance at the ending period						2,600		2,600
Level 3 | Contract Extensions | TeraLogics
Assets and liabilities measured at fair value on a recurring basis
Balance at the Beginning period						2,000
Initial measurement recognized at acquisition							2,000
Adjustment to the provisional acquisition date valuation						(100)
Total remeasurement recognized in earnings						100
Balance at the ending period					2,000	2,000	2,000	2,000
Level 3 | Revenue Targets | TeraLogics
Assets and liabilities measured at fair value on a recurring basis
Balance at the Beginning period						3,100
Initial measurement recognized at acquisition							3,100
Total remeasurement recognized in earnings						(200)
Balance at the ending period					$ 3,100	2,900	$ 3,100	2,900
Assets and liabilities measured at fair value
Assets
Cash equivalents						65,035		65,035	68,194
Marketable securities						14,381		14,381	30,533
Current derivative assets						13,613		13,613	11,543
Noncurrent derivative assets						841		841	13,909
Marketable securities in rabbi trust						553		553	992
Total assets measured at fair value						94,423		94,423	125,171
Liabilities
Current derivative liabilities						13,002		13,002	9,370
Noncurrent derivative liabilities						918		918	13,909
Total liabilities measured at fair value						26,619		26,619	30,786
Assets and liabilities measured at fair value | DTECH
Liabilities
Noncurrent contingent consideration to seller						4,400		4,400	7,507
Assets and liabilities measured at fair value | H4 Global
Liabilities
Noncurrent contingent consideration to seller						799		799
Assets and liabilities measured at fair value | GATR
Liabilities
Noncurrent contingent consideration to seller						2,600		2,600
Assets and liabilities measured at fair value | Contract Extensions | TeraLogics
Liabilities
Noncurrent contingent consideration to seller						2,000		2,000
Assets and liabilities measured at fair value | Revenue Targets | TeraLogics
Liabilities
Noncurrent contingent consideration to seller						2,900		2,900
Assets and liabilities measured at fair value | Level 1
Assets
Cash equivalents						65,035		65,035	68,194
Marketable securities in rabbi trust						553		553	992
Total assets measured at fair value						65,588		65,588	69,186
Assets and liabilities measured at fair value | Level 2
Assets
Marketable securities						14,381		14,381	30,533
Current derivative assets						13,613		13,613	11,543
Noncurrent derivative assets						841		841	13,909
Total assets measured at fair value						28,835		28,835	55,985
Liabilities
Current derivative liabilities						13,002		13,002	9,370
Noncurrent derivative liabilities						918		918	13,909
Total liabilities measured at fair value						13,920		13,920	23,279
Assets and liabilities measured at fair value | Level 3
Liabilities
Total liabilities measured at fair value						12,699		12,699	7,507
Assets and liabilities measured at fair value | Level 3 | DTECH
Liabilities
Noncurrent contingent consideration to seller						4,400		4,400	$ 7,507
Assets and liabilities measured at fair value | Level 3 | H4 Global
Liabilities
Noncurrent contingent consideration to seller						799		799
Assets and liabilities measured at fair value | Level 3 | GATR
Liabilities
Noncurrent contingent consideration to seller						2,600		2,600
Assets and liabilities measured at fair value | Level 3 | Contract Extensions | TeraLogics
Liabilities
Noncurrent contingent consideration to seller						2,000		2,000
Assets and liabilities measured at fair value | Level 3 | Revenue Targets | TeraLogics
Liabilities
Noncurrent contingent consideration to seller						$ 2,900		$ 2,900