Stockholder Rights Plan (Detail) - Narrative - Rights Agreement Expired November 15, 2015 - $ / shares	Nov. 15, 2015	Feb. 15, 1989
Class of Warrant or Right [Line Items]
Number of securities called by each warrant or right		1
Series A Preferred Stock
Class of Warrant or Right [Line Items]
Number of securities called by each warrant or right	0.01
Exercise price of warrants or rights (dollars per share)	$ 150