Information Pertaining to Held to Maturity Securities With Gross Unrealized Losses (Detail) (Corporate Bond, USD $) In Thousands, unless otherwise specified	9 Months Ended	12 Months Ended
	Sep. 30, 2014	Dec. 31, 2013
Corporate Bond
Schedule of Held-to-maturity Securities [Line Items]
Less than 12 months Fair Value	$ 0	$ 28,839
Less than 12 months Gross Unrealized Losses	0	(40)
12 months or longer Fair Value	0	2,614
12 months or longer Gross Unrealized Losses	0	3
Total Fair Value	0	31,453
Total Gross Unrealized Losses	$ 0	$ (43)