Segment Reporting (Details 1) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2013		Mar. 31, 2013	Dec. 31, 2012	Jun. 30, 2012		Mar. 31, 2012	Dec. 31, 2011
Assets
Cash and cash equivalents	$ 249,531		$ 331,311	$ 125,440	$ 199,397		$ 151,883	$ 175,012
Short term investments	0			999
Other assets	112,583			120,906
TOTAL ASSETS	3,666,716			3,221,401
Reportable Segment [Member]
Assets
Total assets for reportable segments	3,304,602			2,974,056
TOTAL ASSETS	$ 3,304,602	[1]			$ 2,919,752	[1]

[1] Segment assets consist of receivables, prepaids, inventories, property, plant and equipment, and mining properties