Restructuring Charges Restructuring Charges (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended	9 Months Ended
	Sep. 30, 2013 position	Sep. 30, 2013	Sep. 30, 2012
Restructuring Cost and Reserve [Line Items]
Number of positions eliminated	160
Costs incurred and charged to expense		$ 4,075	$ 13,872
Restructuring Reserve [Roll Forward]
Accrued liability beginning balance		2,431
Costs incurred and charged to expense, excluding non-cash charges		2,891
Cash payments		(2,806)
Accrued liability ending balance	2,516	2,516
Employee Separation Costs
Restructuring Cost and Reserve [Line Items]
Costs incurred and charged to expense	1,100	2,891	8,099
Restructuring Reserve [Roll Forward]
Accrued liability beginning balance		731
Costs incurred and charged to expense, excluding non-cash charges		2,891
Cash payments		(2,806)
Accrued liability ending balance	816	816
Contract Assignment Costs
Restructuring Cost and Reserve [Line Items]
Costs incurred and charged to expense	0		3,629
Restructuring Reserve [Roll Forward]
Accrued liability beginning balance		1,700
Costs incurred and charged to expense, excluding non-cash charges		0
Cash payments		0
Accrued liability ending balance	1,700	1,700
Asset Related and Other
Restructuring Cost and Reserve [Line Items]
Costs incurred and charged to expense	$ 800	$ 1,184	$ 2,144