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
 3 Months Ended 12 Months Ended
Jun. 07, 2017
Mar. 22, 2017
Mar. 08, 2017
Mar. 31, 2017
Mar. 31, 2016
Dec. 31, 2016
Jan. 27, 2015
Share Repurchase Program [Line Items]              
Share repurchased and retired (in shares)         181,000    
Value of shares repurchased and retired         $ 8,700    
Outstanding common stock acquired, average price (in dollars per share)         $ 48.04    
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   $ 18,331   $ 73,151  
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]              
Common Stock, Dividends, Per Share, Cash Paid (in dollars per share) $ 0.35