XML 72 R56.htm IDEA: XBRL DOCUMENT v3.3.1.900
Shareholders' Equity (Details 4) - Class A common shares - $ / shares
12 Months Ended
Dec. 31, 2015
Dec. 31, 2014
Dec. 31, 2013
Class of Stock      
Weighted average fair value (in dollars per share) $ 4.57 $ 5.06 $ 4.75
Expected term 7 years 7 years 7 years
Dividend Yield 3.00% 3.00% 3.00%
Volatility 35.90% 38.50% 38.00%
Risk-free interest rate 1.90% 2.20% 2.00%