Investments - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Financial Instruments [Line Items]
Period cash equivalents and short-term investments have been in continuous unrealized loss position, years, maximum	1 year
Period cash equivalents and long-term investments have been in continuous unrealized loss position, years, minimum	1 year
Unrealized gains (losses) on investments	$ 27	$ 350	$ 13
CCKF [Member]
Financial Instruments [Line Items]
Non controlling interest	$ 3,900
Percentage of investment in equity affiliate	30.70%
Income (loss) from investment in affiliate	$ (300)
CCKF [Member] | Maximum [Member]
Financial Instruments [Line Items]
Income (loss) from investment in affiliate		$ 100
Municipal Bonds [Member]
Financial Instruments [Line Items]
Period debt obligations mature, years, maximum	1 year
Unrealized gains (losses) on investments	$ 500