Annual report pursuant to Section 13 and 15(d)

Shareholders' Equity (Detail)

v3.3.1.900
Shareholders' Equity (Detail) - USD ($)
 12 Months Ended
Dec. 31, 2015
Dec. 31, 2014
Dec. 31, 2013
Class of Stock [Line Items]      
Preferred Stock, Shares Authorized 500,000 500,000  
Preferred Stock, Shares Issued 0 0 0
Preferred Stock, Par or Stated Value Per Share $ 25 $ 25  
Preferred Stock, Value, Outstanding $ 0 $ 0 $ 0
Shares Paid for Tax Withholding for Share Based Compensation 120,455 231,142  
Computershare Trust Company, N.A [Member]      
Class of Stock [Line Items]      
Class of Warrant or Right, Number of Securities Called by Warrants or Rights 1    
Class of Warrant or Right, Number of Securities Called by Each Warrant or Right 0.0001    
Class of Warrant or Right, Exercise Price of Warrants or Rights $ 7.20    
Minimum Percentage Of Ownership for Rights to become Exercisable 10.00%    
Rights Per Common Share 1    
Redemption Price Per Right $ 0.001    
Series A Junior Participating Preferred Stock [Member]      
Class of Stock [Line Items]      
Preferred Stock, Shares Authorized 15,000