Share Capital - Allocation of Share Based Compensation (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation cost	$ 2,287	$ 3,415	$ 9,791	$ 8,215
Less: Stock-based compensation costs capitalized	(278)	(1,718)	(2,100)	(2,102)
Stock-based compensation costs expensed	2,009	1,697	7,691	6,113
Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation cost	1,961	2,133	5,824	6,314
RSUs [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation cost	$ 326	$ 1,282	$ 3,967	$ 1,901