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Equity Based Plans - Summary of Restricted Stock Granted to Directors, Officers and Employees Pursuant to Its Equity Plans (Details) - $ / shares
12 Months Ended
Dec. 31, 2015
Dec. 31, 2014
Dec. 31, 2013
Equity Based Plans [Abstract]      
Number of shares (in shares) 147,928 159,443 174,938
Weighted average fair value (in dollars per share) $ 41.66 $ 33.29 $ 23.52