Acquisitions - Schedule of Cost of Acquisition, including Fair Value of Contingent Consideration Allocated to Assets Acquired and Liabilities Assumed (Detail) - USD ($) $ in Thousands	Sep. 30, 2016	Jun. 30, 2016	Mar. 10, 2016
Business Acquisition [Line Items]
Goodwill	$ 1,511,380	$ 1,510,279
TowerSec Ltd. [Member]
Business Acquisition [Line Items]
Cash and cash equivalents			$ 472
Other current assets			84
Current assets			556
Property, plant and equipment			205
Goodwill			69,438
Intangible assets			4,600
Other non-current assets			89
Total assets			74,888
Accounts payable			119
Accrued liabilities			66
Total current liabilities			185
Other non-current liabilities			3,723
Total liabilities			3,908
Net assets			$ 70,980