Share Capital - Narrative (Details) (USD $)	Mar. 31, 2015	Dec. 31, 2014	Mar. 31, 2014	Dec. 31, 2013	Oct. 07, 2011
Class of Stock [Line Items]
Preferred stock, authorized	50,000,000
Preferred stock, par value	$ 0.001
Preferred stock, issued	0
Stock Repurchase Program, Remaining Number of Shares Authorized to be Repurchased	352,823
Class A Stock [Member]
Class of Stock [Line Items]
Common Stock, Shares Authorized	50,000,000	50,000,000
Common Stock, Par or Stated Value Per Share	$ 0.001	$ 0.001
Common stock, issued	13,634,831	13,530,688			13,572,265
Common stock, outstanding	13,634,831	13,530,688	13,516,626	13,377,967	13,572,265
Repurchase of class A common stock					675,000
Percentage of repurchase of class A common stock					5.00%
Class B Stock [Member]
Class of Stock [Line Items]
Common Stock, Shares Authorized	99,680	99,680
Common Stock, Par or Stated Value Per Share	$ 0.001	$ 0.001
Common stock, issued	99,680	99,680
Common stock, outstanding	99,680	99,680