Income Taxes (Reconciliation of Net Deferred Tax Assets and Liabilities) (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Income Taxes
Deferred tax assets - current	$ 59,203	$ 57,683
Deferred tax liabilities - current	78,675	59,673
Deferred tax liabilities - current	(19,472)	(1,990)
Deferred tax assets - noncurrent	66,015	58,468
Deferred tax liabilities - noncurrent	145,559	147,332
Deferred tax liabilities - noncurrent	(79,544)	(88,864)
Net deferred tax liabilities	$ (99,016)	$ (90,854)