Business Combinations, Bluetube (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Allocation of Total Purchase Price Consideration [Abstract]
Goodwill	$ 275,205	$ 269,383	$ 236,130
Minimum [Member]
Allocation of Total Purchase Price Consideration [Abstract]
Intangible assets, useful lives	1 year
Maximum [Member]
Allocation of Total Purchase Price Consideration [Abstract]
Intangible assets, useful lives	10 years
BlueTube [Member]
Business Combinations [Abstract]
Date of acquisition	Oct. 12, 2016
Cash paid for acquisition	$ 7,200
Initial fair value estimate of additional earnings-based contingent consideration	1,900
Maximum payout of earnings-based contingent consideration	2,700
Transaction costs	$ 500
Period to realize additional earnings-based contingent consideration	12 months
Allocation of Total Purchase Price Consideration [Abstract]
Acquired tangible assets	$ 1,000
Acquired intangible assets	3,100
Liabilities assumed	(700)
Goodwill	5,700
Total purchase price	9,100
Tax deductible amount of Goodwill	$ 4,000
BlueTube [Member] | Minimum [Member]
Allocation of Total Purchase Price Consideration [Abstract]
Intangible assets, useful lives	6 months
BlueTube [Member] | Maximum [Member]
Allocation of Total Purchase Price Consideration [Abstract]
Intangible assets, useful lives	5 years