Acquisition - Net Assets Acquired (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Jul. 14, 2017	Dec. 31, 2016
Preliminary allocation of the purchase price
Goodwill	$ 1,251,325		$ 1,196,024
RowdMap
Preliminary allocation of the purchase price
Cash		$ 4,107
Accounts receivable		2,526
Prepaid expenses and other assets		1,212
Other long-term assets		12
Property and equipment		263
Intangible assets		19,510
Total identifiable assets acquired		27,630
Accounts payable and accrued liabilities		4,491
Deferred tax liabilities		3,688
Total liabilities assumed		8,179
Net identifiable assets acquired		19,451
Goodwill		54,673
Net assets acquired		$ 74,124