Fair Value of Financial Assets (Detail) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2014	Dec. 31, 2013
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Assets, fair value	$ 19,208	$ 24,467
Fair Value, Inputs, Level 1 [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Assets, fair value	15,495	4,588
Fair Value, Inputs, Level 2 [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Assets, fair value	3,713	19,879
Fair Value, Inputs, Level 3 [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Assets, fair value	0
Money Market Funds [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Assets, fair value	15,495	4,588
Money Market Funds [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Assets, fair value	15,495	4,588
Money Market Funds [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Assets, fair value	0
Money Market Funds [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Assets, fair value	0
Time deposits [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Assets, fair value	0	6,540
Time deposits [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Assets, fair value	0	0
Time deposits [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Assets, fair value	0	6,540
Time deposits [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Assets, fair value	0	0
Corporate Bonds [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Assets, fair value	2,013	6,706
Corporate Bonds [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Assets, fair value	0	0
Corporate Bonds [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Assets, fair value	2,013	6,706
Corporate Bonds [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Assets, fair value	0	0
U.S. Federal Agencies [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Assets, fair value	0	0
U.S. Federal Agencies [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Assets, fair value	0	0
U.S. Federal Agencies [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Assets, fair value	0	0
U.S. Federal Agencies [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Assets, fair value	0	0
Foreign Bonds and Notes [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Assets, fair value	0	4,832
Foreign Bonds and Notes [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Assets, fair value	0	0
Foreign Bonds and Notes [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Assets, fair value	0	4,832
Foreign Bonds and Notes [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Assets, fair value	0	0
Variable Rate Demand Notes [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Assets, fair value	1,700	1,801
Variable Rate Demand Notes [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Assets, fair value	0	0
Variable Rate Demand Notes [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Assets, fair value	1,700	1,801
Variable Rate Demand Notes [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Assets, fair value	0	0
Mutual Funds Held in Rabbi Trust [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Assets, fair value	410	442
Mutual Funds Held in Rabbi Trust [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Assets, fair value	410	442
Mutual Funds Held in Rabbi Trust [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Assets, fair value	0
Mutual Funds Held in Rabbi Trust [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Assets, fair value	$ 0