Summary of Significant Accounting Policies - Schedule of Gross Unrealized Holding Losses and Fair Value of Marketable Securities (Detail) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Schedule of Available-for-sale Securities [Line Items]
Equity securities, Total, Unrealized Losses	$ 1,100
Equity securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Equity securities, Less than 12 Months Fair Value	3,099	$ 1,380
Equity securities, Less than 12 Months Unrealized Losses	987	197
Equity securities, 12 Months or Greater Fair Value	345	146
Equity securities, 12 Months or Greater Unrealized Losses	154	98
Equity securities, Total, Fair Value	3,444	1,526
Equity securities, Total, Unrealized Losses	$ 1,141	$ 295