Fair Value Measurements - Additional Information (Detail) - USD ($)	1 Months Ended	3 Months Ended			6 Months Ended
	Aug. 31, 2016	Dec. 31, 2016	Sep. 30, 2016	Dec. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Jun. 30, 2016
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Purchase of convertible debt security	$ 15,000,000				$ 15,000,000
Available-for-sale debt security		$ 15,000,000			$ 15,000,000
Contractual maturity date					Aug. 18, 2018
Gains or losses recognized		0		$ 0	$ 0	$ 0
TowerSec Ltd. [Member] | Estimate of Fair Value Measurement [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of contingent consideration liability		27,700,000			27,700,000		$ 27,700,000
Red Bend Ltd. [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of contingent consideration liability		30,000,000			30,000,000
Red Bend Ltd. [Member] | Estimate of Fair Value Measurement [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of contingent consideration liability		30,000,000	$ 30,000,000		30,000,000		18,400,000
Southern Vision Systems Inc [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of contingent consideration liability		10,000,000			10,000,000
Payment towards contingent consideration liability			2,100,000
Southern Vision Systems Inc [Member] | Estimate of Fair Value Measurement [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of contingent consideration liability		4,700,000			4,700,000		3,000,000
Duran Audio BV [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Payment towards contingent consideration liability			$ 100,000
Duran Audio BV [Member] | Estimate of Fair Value Measurement [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of contingent consideration liability		1,500,000			1,500,000		1,600,000
IPSG/VFX [Member] | Estimate of Fair Value Measurement [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of contingent consideration liability		$ 0			$ 0		$ 0