Restructuring (Narrative) (Details) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015 USD ($)	Sep. 30, 2014 USD ($)	Sep. 30, 2015 USD ($) position	Sep. 30, 2014 USD ($)	Dec. 31, 2014 USD ($)
Restructuring Cost and Reserve [Line Items]
Restructuring	$ 13,766	$ 3,124	$ 62,251	$ 17,285
Restructuring Reserve	20,138		20,138		$ 2,780
Employee Severance and Related Costs [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring			46,756
Consolidation of Leased Facilities [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring			$ 14,703
2014 Restructuring Program [Member]
Restructuring Cost and Reserve [Line Items]
Number of full-time positions eliminated | position			325
Restructuring costs incurred since inception	22,200		$ 22,200
Restructuring Reserve	1,144		1,144		2,780
2014 Restructuring Program [Member] | Employee Severance and Related Costs [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring			2,060
2014 Restructuring Program [Member] | Consolidation of Leased Facilities [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring			$ 0
2015 Restructuring Program [Member]
Restructuring Cost and Reserve [Line Items]
Number of full-time positions eliminated | position			700
Restructuring	14,000		$ 60,500
Restructuring Reserve	18,994		18,994		$ 0
2015 Restructuring Program [Member] | Minimum [Member]
Restructuring Cost and Reserve [Line Items]
Total expected restructuring cost	66,000		66,000
2015 Restructuring Program [Member] | Maximum [Member]
Restructuring Cost and Reserve [Line Items]
Total expected restructuring cost	70,000		70,000
2015 Restructuring Program [Member] | Employee Severance and Related Costs [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring			44,696
2015 Restructuring Program [Member] | Employee Severance and Related Costs [Member] | Minimum [Member]
Restructuring Cost and Reserve [Line Items]
Total expected restructuring cost	49,000		49,000
2015 Restructuring Program [Member] | Employee Severance and Related Costs [Member] | Maximum [Member]
Restructuring Cost and Reserve [Line Items]
Total expected restructuring cost	51,000		51,000
2015 Restructuring Program [Member] | Consolidation of Leased Facilities [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring			14,703
2015 Restructuring Program [Member] | Consolidation of Leased Facilities [Member] | Minimum [Member]
Restructuring Cost and Reserve [Line Items]
Total expected restructuring cost	17,000		17,000
2015 Restructuring Program [Member] | Consolidation of Leased Facilities [Member] | Maximum [Member]
Restructuring Cost and Reserve [Line Items]
Total expected restructuring cost	19,000		19,000
Enterprise and Service Provider Division [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Reserve	20,100		20,100
Enterprise and Service Provider Division [Member] | 2014 Restructuring Program [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring	(263)	3,122	1,747	11,093
Enterprise and Service Provider Division [Member] | 2015 Restructuring Program [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring	$ 13,714	$ 0	$ 59,580	$ 0