Annual report pursuant to Section 13 and 15(d)

Shareholders' Equity Shareholders' Equity (Narrative) (Details)

v3.6.0.2
Shareholders' Equity Shareholders' Equity (Narrative) (Details) - USD ($)
$ / shares in Units, $ in Thousands
 1 Months Ended 3 Months Ended 12 Months Ended 34 Months Ended
Mar. 08, 2017
Feb. 28, 2015
Dec. 31, 2016
Sep. 30, 2016
Jun. 30, 2016
Mar. 31, 2016
Dec. 31, 2015
Sep. 30, 2015
Jun. 30, 2015
Mar. 31, 2015
Dec. 31, 2016
Dec. 31, 2015
Dec. 31, 2014
Jul. 16, 2014
Jan. 27, 2015
Sep. 27, 2011
Class of Stock [Line Items]                                
Dividends declared per common share   $ 10.00 $ 0.35 $ 0.35 $ 0.35 $ 0.35 $ 0.35 $ 0.35 $ 0.35 $ 10.35 $ 1.40 $ 11.40 $ 1.1      
Payments of Dividends                     $ 73,151 $ 597,864 $ 57,824      
Quarterly dividends                       $ 1.40        
Stock Repurchased and Retired During Period, Value                     $ 16,567 $ 58,510 $ 55,467      
Treasury Stock Acquired, Average Cost Per Share                     $ 46.45 $ 61.73 $ 54.87      
Class of Warrant or Right, Number of Securities Called by Warrants or Rights     1               1          
Percentage of common stock to be acquired for the exercise of the rights                     15.00%          
Discount on market price common stock for the purchase of rights                     50.00%          
10 Million Share Program Approved 9/27/2011 [Member]                                
Class of Stock [Line Items]                                
Stock Repurchase Program, Number of Shares Authorized to be Repurchased                               10,000,000
Stock Repurchased and Retired During Period, Value                           $ 451,000    
Treasury Stock Acquired, Average Cost Per Share                           $ 45.10    
4 Million Share Program Approved 1/27/2015 [Member]                                
Class of Stock [Line Items]                                
Stock Repurchase Program, Number of Shares Authorized to be Repurchased                             4,000,000  
Stock Repurchase Program, Remaining Number of Shares Authorized to be Repurchased     2,700,000               2,700,000          
Subsequent Event [Member]                                
Class of Stock [Line Items]                                
Dividends declared per common share $ 0.35