Income Taxes (Sources of Income) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Income Before Income Tax Domestic And Foreign [Line Items]
Income before income taxes	$ 141,355	$ 127,814	$ (5,934)	$ 164,425	$ (41,384)	$ 225,867	$ 101,298	$ 225,666	$ 427,660	$ 511,447	$ 305,528
Non-U.S.
Income Before Income Tax Domestic And Foreign [Line Items]
Income before income taxes									401,778	474,412	242,353
United States
Income Before Income Tax Domestic And Foreign [Line Items]
Income before income taxes									$ 25,882	$ 37,035	$ 63,175