Share Capital - Cash Distribution - Additional Information (Detail) (USD $) In Thousands, except Share data, unless otherwise specified	9 Months Ended	12 Months Ended		0 Months Ended	9 Months Ended	12 Months Ended
	Sep. 30, 2014	Dec. 31, 2013	Jun. 24, 2013 Cash Distribution [Member]	Jun. 27, 2013 Additional Paid-in Capital [Member]	Sep. 30, 2014 Additional Paid-in Capital [Member]	Dec. 31, 2013 Additional Paid-in Capital [Member]
Class of Stock [Line Items]
Cash distribution approval date	Jun. 14, 2013
Cash distribution record date	Jun. 24, 2013
Total amount of cash distribution paid to shareholders of record		$ (200,000)		$ 200,000		$ (200,000)
Distribution payment per share		$ 3.92			$ 3.92	$ 3.92
Common stock, shares outstanding	51,185,922	51,081,878	51,081,878