Cash Equivalents and Investments (Narrative) (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Cash and Cash Equivalents [Abstract]
Accumulated Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment, Net of Tax	$ 435,000	$ 364,000
Gains (losses) on sales of available-for-sale securities	$ 997,000	$ 30,000	$ 0