Commitments and Contingencies - Maturity of Obligations (Details) $ in Thousands	Jun. 30, 2017 USD ($)
Leases, net of Sublease Income
Remainder of 2017	$ 19,368
2018	43,166
2019	45,418
2020	45,119
2021	43,637
Thereafter	167,473
Operating leases, future minimum payments due, net of sublease income, due, total	364,181
Purchase Obligations
Remainder of 2017	12,879
2018	19,093
2019	10,614
2020	5,155
2021	3,172
Thereafter	162
Unrecorded unconditional purchase obligation, total	51,075
Other
Remainder of 2017	286
2018	572
2019	572
2020	572
2021	572
Thereafter	1,621
Other commitment, total	4,195
Total
Remainder of 2017	32,533
2018	62,831
2019	56,604
2020	50,846
2021	47,381
Thereafter	169,256
Contractual obligation, total	419,451
Unrecorded Unconditional Purchase Obligation [Line Items]
Purchase obligations, cancellation policy	16,200
Knowledge User Conferences
Unrecorded Unconditional Purchase Obligation [Line Items]
Purchase obligations, cancellation policy	$ 7,800