Consolidated Majority-Owned Subsidiaries - Summary of Estimated Fair Value of Assets Acquired and Liabilities Assumed at the Acquisition Date (Detail) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2014	Dec. 31, 2013	Mar. 15, 2013 Scenario, Plan AquaBounty Technologies, Inc.	Mar. 15, 2013 Scenario, Adjustment AquaBounty Technologies, Inc.	Mar. 15, 2013 Scenario, Actual AquaBounty Technologies, Inc.
Business Acquisition [Line Items]
Cash			$ 5,419		$ 5,419
Short-term investments			14		14
Trade receivables			4		4
Other receivables			9		9
Prepaid expenses and other			200		200
Property, plant and equipment			1,241		1,241
Intangible assets			14,900		14,900
Other non-current assets			22		22
Total assets acquired			21,809		21,809
Accounts payable			156		156
Accrued compensation			94		94
Other accrued liabilities			395		395
Long term debt			2,199	(845)	1,354
Total liabilities assumed			2,844	(845)	1,999
Net assets acquired			18,965	845	19,810
Goodwill	98,778	13,823	13,846	(845)	13,001
Total consideration			$ 32,811		$ 32,811