Fair Value of Financial Instruments (Details) - USD ($) $ in Thousands				3 Months Ended	12 Months Ended
	Feb. 02, 2016	Dec. 21, 2015	Nov. 04, 2015	Dec. 31, 2016	Sep. 30, 2016
DTECH
Assets and liabilities measured at fair value on a recurring basis
Volatility earning metrics				20.00%	18.00%
H4 Global
Assets and liabilities measured at fair value on a recurring basis
Period for contingent consideration contracts			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%	17.00%
Initial measurement recognized at acquisition		$ 33,900
GATR
Assets and liabilities measured at fair value on a recurring basis
Volatility earning metrics				17.00%	17.00%
Period for contingent consideration contracts	12 months
Initial measurement recognized at acquisition	$ 220,500
Level 2
Debt instruments
Fair Value				$ 199,300	$ 210,000
Carrying value				200,900	201,000
Level 3
Assets and liabilities measured at fair value on a recurring basis
Balance at the Beginning period				11,267
Cash paid to seller				(2,500)
Total remeasurement (gain) loss recognized in earnings				(1,314)
Balance at the ending period				7,453	11,267
Level 3 | DTECH
Assets and liabilities measured at fair value on a recurring basis
Balance at the Beginning period				2,000
Total remeasurement (gain) loss recognized in earnings				(700)
Balance at the ending period				1,300	2,000
Level 3 | H4 Global
Assets and liabilities measured at fair value on a recurring basis
Balance at the Beginning period				567
Total remeasurement (gain) loss recognized in earnings				(114)
Balance at the ending period				453	567
Level 3 | GATR
Assets and liabilities measured at fair value on a recurring basis
Balance at the Beginning period				3,200
Total remeasurement (gain) loss recognized in earnings				(400)
Balance at the ending period				2,800	3,200
Level 3 | Contract extensions | TeraLogics
Assets and liabilities measured at fair value on a recurring basis
Balance at the Beginning period				1,400
Total remeasurement (gain) loss recognized in earnings				100
Balance at the ending period				1,500	1,400
Level 3 | Revenue Targets | TeraLogics
Assets and liabilities measured at fair value on a recurring basis
Balance at the Beginning period				4,100
Cash paid to seller				(2,500)
Total remeasurement (gain) loss recognized in earnings				(200)
Balance at the ending period				1,400	4,100
Assets and liabilities measured at fair value
Assets
Cash equivalents				65,773	57,455
Marketable securities				12,353	12,996
Current derivative assets				4,473	14,770
Noncurrent derivative assets				1,151	1,201
Marketable securities in rabbi trust				1,297	4
Total assets measured at fair value				85,047	86,426
Liabilities
Current derivative liabilities				4,066	13,752
Noncurrent derivative liabilities				1,151	1,334
Total liabilities measured at fair value				12,670	26,353
Assets and liabilities measured at fair value | DTECH
Liabilities
Noncurrent contingent consideration to seller				1,300	2,000
Assets and liabilities measured at fair value | H4 Global
Liabilities
Noncurrent contingent consideration to seller				453	567
Assets and liabilities measured at fair value | GATR
Liabilities
Noncurrent contingent consideration to seller				2,800	3,200
Assets and liabilities measured at fair value | Contract extensions | TeraLogics
Liabilities
Noncurrent contingent consideration to seller				1,500	1,400
Assets and liabilities measured at fair value | Revenue Targets | TeraLogics
Liabilities
Noncurrent contingent consideration to seller				1,400	4,100
Assets and liabilities measured at fair value | Level 1
Assets
Cash equivalents				65,773	57,455
Marketable securities in rabbi trust				1,297	4
Total assets measured at fair value				67,070	57,459
Assets and liabilities measured at fair value | Level 2
Assets
Marketable securities				12,353	12,996
Current derivative assets				4,473	14,770
Noncurrent derivative assets				1,151	1,201
Total assets measured at fair value				17,977	28,967
Liabilities
Current derivative liabilities				4,066	13,752
Noncurrent derivative liabilities				1,151	1,334
Total liabilities measured at fair value				5,217	15,086
Assets and liabilities measured at fair value | Level 3
Liabilities
Total liabilities measured at fair value				7,453	11,267
Assets and liabilities measured at fair value | Level 3 | DTECH
Liabilities
Noncurrent contingent consideration to seller				1,300	2,000
Assets and liabilities measured at fair value | Level 3 | H4 Global
Liabilities
Noncurrent contingent consideration to seller				453	567
Assets and liabilities measured at fair value | Level 3 | GATR
Liabilities
Noncurrent contingent consideration to seller				2,800	3,200
Assets and liabilities measured at fair value | Level 3 | Contract extensions | TeraLogics
Liabilities
Noncurrent contingent consideration to seller				1,500	1,400
Assets and liabilities measured at fair value | Level 3 | Revenue Targets | TeraLogics
Liabilities
Noncurrent contingent consideration to seller				$ 1,400	$ 4,100