Annual report pursuant to Section 13 and 15(d)

Equity Structure and Transactions - Additional Information (Details)

v3.3.1.900
Equity Structure and Transactions - Additional Information (Details) - USD ($)
$ / shares in Units, $ in Thousands
12 Months Ended
Dec. 31, 2015
Dec. 31, 2014
Dec. 31, 2013
Equity Structure And Transactions [Line Items]      
Preferred stock, shares authorized 20,000,000 20,000,000  
Preferred stock, par value $ 0.00001 $ 0.00001  
Preferred stock, issued 0 0  
Cash dividends paid   $ 30,260 $ 58,846
Common Stock, Regular      
Equity Structure And Transactions [Line Items]      
Paid cash dividends, per share $ 0 $ 0.40 $ 0.36
Common Stock, Special      
Equity Structure And Transactions [Line Items]      
Paid cash dividends, per share     $ 0.42
Cash dividends paid     $ 31,800