Other Non-Operating Income (Expense) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended							9 Months Ended		12 Months Ended
	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Sep. 30, 2013	Sep. 30, 2012	Dec. 31, 2012	Dec. 31, 2011
Other Non-Operating Income (Expense) [Abstract]
Foreign currency gain (loss), net	$ 7,886				$ 3,111			$ (9,350)	$ 3,179
(Loss) gain on sales of marketable equity securities	0				(28)			879	477
Gain (loss) on sales or write-downs of cost method investments, net	18				(112)			(160)	6,760
Other, net	206				1,192			(200)	1,700
Total Other Non-Operating Income (Expense)	$ 8,110	$ (12,858)	$ (4,083)	$ (17,572)	$ 4,163	$ (635)	$ 8,588	$ (8,831)	$ 12,116	$ (5,456)	$ (55,200)