Acquisitions - Schedule of Cost of Acquisition, including Fair Value of Contingent Consideration Allocated to Assets Acquired and Liabilities Assumed (Detail) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2014	Jun. 30, 2014	Sep. 30, 2014 AMX LLC [Member]	Jun. 13, 2014 AMX LLC [Member]
Business Acquisition [Line Items]
Cash and cash equivalents				$ 4,351
Accounts receivable, net				27,203
Inventories, net			4,200	29,100
Other current assets				4,877
Current assets				65,531
Property, plant and equipment, net			2,700	28,189
Goodwill	526,040	540,952		241,122
Intangibles				101,030
Other assets				4,275
Total assets				440,147
Accounts payable				11,834
Accrued liabilities				9,698
Total current liabilities				21,532
Other non-current liabilities				45,674
Total liabilities				67,206
Net assets				$ 372,941