Share Capital - Summary of ordinary shares issued and outstanding (Details) - shares		6 Months Ended
		Jun. 30, 2015	Jun. 30, 2014
Summary of ordinary shares issued and outstanding:
Balance, issued, beginning of period (in shares)		255,182,955	278,253,000
Balance, outstanding, beginning of period (in shares)		255,182,955	278,253,000
Exercise of options (in shares)		220,000	424,000
Net issuance of restricted shares (in shares)		1,536,000	1,246,000
Share buybacks (in shares)	[1]	(2,982,000)	(24,740,000)
Issue of shares (in shares)		49,935,000	0
Balance, outstanding, end of period (in shares)		303,891,887
Balance, issued, end of period (in shares)		303,891,887

[1] Includes share buybacks associated with authorized share buyback programs as well as purchases related to satisfying tax withholding obligations of employees in connection with the vesting of restricted shares granted under the Company's equity compensation programs.