Acquisitions - Additional Information (Detail) $ / shares in Units, € in Millions										3 Months Ended			9 Months Ended		12 Months Ended
	Mar. 10, 2016 USD ($)	Jun. 10, 2015 USD ($)	Jun. 01, 2015 USD ($)	Jun. 01, 2015 EUR (€)	Apr. 08, 2015 USD ($) $ / shares shares	Feb. 26, 2015 USD ($) $ / shares shares	Feb. 01, 2015 USD ($)	Feb. 01, 2015 EUR (€)	Dec. 30, 2014 USD ($)	Mar. 31, 2016 USD ($) shares	Sep. 30, 2015 USD ($)	Sep. 30, 2015 EUR (€)	Mar. 31, 2016 USD ($) shares	Mar. 31, 2015 USD ($)	Jun. 30, 2015 USD ($) shares	Jun. 01, 2015 EUR (€)	Feb. 01, 2015 EUR (€)
Business Acquisition [Line Items]
Preliminary valuation of contingent consideration													$ 6,800,000
Assumed debt paid off at closing													$ 35,125,000	$ 543,610,000
Common stock, shares issued | shares										101,135,877			101,135,877		100,699,641
Goodwill										$ 1,426,202,000			$ 1,426,202,000		$ 1,287,180,000
Measurement Period Adjustments [Member]
Business Acquisition [Line Items]
Cumulative reduction in amortization expense										1,200,000			$ 2,000,000
TowerSec Ltd. [Member]
Business Acquisition [Line Items]
Business acquisition date													Mar. 10, 2016
Purchase consideration, total	$ 45,000,000
Cash paid to acquire entity	37,900,000
Holdback Amounts in escrow	2,300,000
Deferred consideration amount	$ 3,000,000
Number of years expected to occur certain days	18 months
Approximately third-party debt assumed	$ 2,600,000
Preliminary valuation of contingent consideration	20,000,000
Acquired intangible assets	6,000,000
Acquisition costs incurred													$ 600,000
Goodwill amount deductible for tax purposes	0
Goodwill	60,936,000
TowerSec Ltd. [Member] | Internally Developed Software
Business Acquisition [Line Items]
Acquired intangible assets	$ 6,000,000
Approximate useful life	6 years
TowerSec Ltd. [Member] | Maximum [Member]
Business Acquisition [Line Items]
Acquisition earn-out contingent payable	$ 30,000,000
Southern Vision Systems Inc [Member]
Business Acquisition [Line Items]
Business acquisition date													Jun. 10, 2015
Purchase consideration, total		$ 20,000,000
Cash paid to acquire entity		19,500,000
Holdback Amounts in escrow		$ 2,400,000
Number of years expected to occur certain days		18 months
Acquisition earn-out contingent payable										10,000,000			$ 10,000,000
Preliminary valuation of contingent consideration		$ 0								0			0
Acquired intangible assets		8,360,000
Acquisition costs incurred															300,000
Increase (decrease) to purchase price											$ 100,000
Goodwill		13,244,000
Acquisition earn-out contingent payable										10,000,000			$ 10,000,000
Southern Vision Systems Inc [Member] | Internally Developed Software
Business Acquisition [Line Items]
Acquired intangible assets		$ 7,700,000
Approximate useful life		5 years
Southern Vision Systems Inc [Member] | Distributor Relationships
Business Acquisition [Line Items]
Acquired intangible assets		$ 600,000
Approximate useful life		2 years
Southern Vision Systems Inc [Member] | Trade Names [Member]
Business Acquisition [Line Items]
Acquired intangible assets		$ 100,000
Approximate useful life		6 months
Bang & Olufsen Automotive Assets [Member]
Business Acquisition [Line Items]
Business acquisition date													Jun. 01, 2015
Purchase consideration, total			$ 165,700,000	€ 150.8
Holdback Amounts in escrow | €																€ 12.5
Number of years expected to occur certain days			15 months	15 months
Acquired intangible assets			$ 129,700,000
Acquisition costs incurred															800,000
Increase (decrease) to purchase price											500,000	€ 0.5
Goodwill amount deductible for tax purposes			13,000,000
Goodwill			13,006,000
Bang & Olufsen Automotive Assets [Member] | Customer Relationships [Member]
Business Acquisition [Line Items]
Acquired intangible assets			$ 129,700,000
Approximate useful life			7 years	7 years
Symphony Teleca Corporation [Member]
Business Acquisition [Line Items]
Business acquisition date					Apr. 08, 2015
Purchase consideration, total					$ 720,800,000
Cash paid to acquire entity					299,700,000
Holdback Amounts in escrow										42,000,000			$ 42,000,000
Approximately third-party debt assumed					115,600,000
Acquired intangible assets					202,900,000
Acquisition costs incurred															$ 13,800,000
Goodwill amount deductible for tax purposes					0
Estimated purchase price paid at closing					491,500,000
Number of shares of common stock to acquire entity					191,800,000
Assumed debt paid off at closing					115,600,000
Acquired of cash					61,900,000
Estimated adjustments to purchase price					$ 0
Business combination purchase price and earn out										231,100,000			23,300,000
Final base price adjustment										0
Common stock, shares issued | shares					1,410,161
Common stock, closing price per share | $ / shares					$ 136.00
Goodwill					$ 598,849,000
Symphony Teleca Corporation [Member] | Restricted Cash | Non Controlling Interest [Member]
Business Acquisition [Line Items]
Cash paid to acquire entity					14,800,000
Symphony Teleca Corporation [Member] | Escrow One [Member]
Business Acquisition [Line Items]
Holdback Amounts in escrow placed other										31,200,000			31,200,000
Symphony Teleca Corporation [Member] | Escrow Two [Member]
Business Acquisition [Line Items]
Holdback Amounts in escrow placed other										21,000,000			21,000,000
Symphony Teleca Corporation [Member] | Trade Names [Member]
Business Acquisition [Line Items]
Acquired intangible assets					$ 14,600,000
Approximate useful life					9 years
Symphony Teleca Corporation [Member] | Customer Relationships [Member]
Business Acquisition [Line Items]
Acquired intangible assets					$ 183,100,000
Symphony Teleca Corporation [Member] | Technology [Member]
Business Acquisition [Line Items]
Acquired intangible assets					$ 4,200,000
Approximate useful life					3 years
Symphony Teleca Corporation [Member] | Covenant Not To Compete
Business Acquisition [Line Items]
Acquired intangible assets					$ 1,000,000
Approximate useful life					4 years
Symphony Teleca Corporation [Member] | Maximum [Member] | Customer Relationships [Member]
Business Acquisition [Line Items]
Approximate useful life					11 years
Symphony Teleca Corporation [Member] | Minimum [Member] | Customer Relationships [Member]
Business Acquisition [Line Items]
Approximate useful life					12 years
Red Bend Ltd. [Member]
Business Acquisition [Line Items]
Business acquisition date						Feb. 26, 2015
Cash paid to acquire entity						$ 71,000,000
Holdback Amounts in escrow						$ 16,000,000
Number of years expected to occur certain days						18 months
Preliminary valuation of contingent consideration						$ 20,900,000				16,700,000			16,700,000
Acquired intangible assets						30,500,000
Goodwill amount deductible for tax purposes						0
Goodwill						205,907,000
Purchase price						195,300,000
Common stock shares consideration, amount						124,300,000
Acquisition, third party debt assumed and paid off						5,600,000
Acquisition earn-out contingent payable										30,000,000			$ 30,000,000
Post-Closing Adjustment						$ 400,000
Shares of common stock transferred | shares | shares						897,424
Issuance of common shares from treasury stock | shares | shares						839,287
Restricted stock units vested | shares						58,137
Fair market value of transferred shares of common stock | $ / shares | $ / shares						$ 137.78
Total revaluation adjustment						$ 4,000,000
Red Bend Ltd. [Member] | Pre-acquisition [Member]
Business Acquisition [Line Items]
Fair value of awards associated with services						600,000
Red Bend Ltd. [Member] | Post-acquisition [Member]
Business Acquisition [Line Items]
Fair value of awards associated with services						1,900,000
Red Bend Ltd. [Member] | Trade Names [Member]
Business Acquisition [Line Items]
Acquired intangible assets						$ 100,000
Approximate useful life						10 months
Red Bend Ltd. [Member] | Customer Relationships [Member]
Business Acquisition [Line Items]
Acquired intangible assets						$ 900,000
Approximate useful life						8 years
Red Bend Ltd. [Member] | Technology [Member]
Business Acquisition [Line Items]
Acquired intangible assets						$ 29,500,000
Approximate useful life						8 years
S1nn GmbH & Co. KG [Member]
Business Acquisition [Line Items]
Business acquisition date													Feb. 01, 2015
Purchase consideration, total							$ 55,400,000	€ 49.0
Holdback Amounts in escrow							$ 4,600,000										€ 4.1
IPSG/VFX [Member]
Business Acquisition [Line Items]
Preliminary valuation of contingent consideration										$ 0	$ 0		$ 0
IPSG/VFX [Member] | Harman International Industries Pty Ltd [Member]
Business Acquisition [Line Items]
Business acquisition date													Dec. 30, 2014
Acquisition earn-out contingent payable									$ 0
Purchase price									$ 5,000,000
Holdback percentage of contingent payable									15.00%
IPSG/VFX [Member] | Maximum [Member] | Harman International Industries Pty Ltd [Member]
Business Acquisition [Line Items]
Number of years expected to occur certain days									18 months
Acquisition earn-out contingent payable									$ 8,000,000