Quarterly report pursuant to Section 13 or 15(d)

Shareholders' Equity (Narrative) (Details)

v3.7.0.1
Shareholders' Equity (Narrative) (Details) - USD ($)
$ / shares in Units, $ in Thousands
 6 Months Ended 12 Months Ended
Jun. 21, 2017
Jun. 07, 2017
Jun. 30, 2017
Jun. 30, 2016
Dec. 31, 2016
Sep. 06, 2017
Jul. 06, 2017
Jan. 27, 2015
Share Repurchase Program [Line Items]                
Share repurchased and retired (in shares)       232,000        
Value of shares repurchased and retired       $ 11,100        
Outstanding common stock acquired, average price (in dollars per share)       $ 47.92        
Stock Repurchase Program, Remaining Number of Shares Authorized to be Repurchased (in shares)     2,700,000          
Common Stock, Dividends, Per Share, Cash Paid (in dollars per share)   $ 0.35            
Dividends, Common Stock, Cash $ 18,300   $ 36,664   $ 73,151      
Dividends Payable, Amount Per Share (in dollars per share)             $ 0.35  
4 Million Share Program Approved 1/27/2015 [Member]                
Share Repurchase Program [Line Items]                
Stock Repurchase Program, Number of Shares Authorized to be Repurchased (in shares)               4,000,000
Subsequent Event [Member]                
Share Repurchase Program [Line Items]                
Dividends Payable, Amount Per Share (in dollars per share)           $ 0.35