Purchase of Common Shares (Details) (USD $) In Millions, except Share data, unless otherwise specified	1 Months Ended	12 Months Ended
	Oct. 31, 2014	Dec. 31, 2014
Stock Repurchase Program [Abstract]
Stock repurchase program, authorized amount	$ 40
Stock repurchase program, expected duration	5 years
Stock repurchased during period, shares		43,500
Stock repurchased during period, average cost per share		$ 9.98