Significant Accounting Policies (Details 3)
$ in Thousands |
3 Months Ended |
12 Months Ended |
|
Dec. 31, 2015
USD ($)
|
Sep. 30, 2015
USD ($)
|
Jun. 30, 2015
USD ($)
|
Mar. 31, 2015
USD ($)
|
Dec. 31, 2014
USD ($)
|
Sep. 30, 2014
USD ($)
|
Jun. 30, 2014
USD ($)
|
Mar. 31, 2014
USD ($)
|
Dec. 31, 2015
USD ($)
segment
|
Dec. 31, 2014
USD ($)
|
Dec. 31, 2013
USD ($)
|
| Property and equipment |
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|
|
|
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|
|
|
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| Costs incurred during the period |
$ 7,529
|
$ 7,082
|
$ 6,466
|
$ 6,134
|
$ 5,403
|
$ 5,726
|
$ 5,818
|
$ 5,674
|
$ 27,211
|
$ 22,621
|
$ 19,472
|
| Capitalized Content Development Costs |
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| Useful life of capitalized content development costs |
|
|
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5 years
|
|
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| Impairment of Long-Lived Assets |
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| Impairments of long-lived assets |
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|
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$ 0
|
0
|
|
| Segment and Geographic Information |
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| Number of Reportable Segments | segment |
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1
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| Minimum |
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| Revenue Recognition and Deferred Revenue |
|
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| Term of revenue contracts |
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10 years
|
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| Maximum |
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| Revenue Recognition and Deferred Revenue |
|
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| Term of revenue contracts |
|
|
|
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15 years
|
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| Computer hardware | Minimum |
|
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| Property and equipment |
|
|
|
|
|
|
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| Useful life |
|
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|
3 years
|
|
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| Computer hardware | Maximum |
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| Property and equipment |
|
|
|
|
|
|
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|
|
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| Useful life |
|
|
|
|
|
|
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|
5 years
|
|
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| Furniture and office equipment | Minimum |
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|
|
|
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| Property and equipment |
|
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|
|
|
|
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|
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| Useful life |
|
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|
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|
5 years
|
|
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| Furniture and office equipment | Maximum |
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|
|
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| Property and equipment |
|
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|
|
|
|
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|
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| Useful life |
|
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|
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|
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|
7 years
|
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| Leasehold improvements | Minimum |
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| Property and equipment |
|
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|
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| Useful life |
|
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|
4 years
|
|
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| Leasehold improvements | Maximum |
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| Property and equipment |
|
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|
|
|
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|
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| Useful life |
|
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|
|
|
|
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|
10 years
|
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| Internally-developed software |
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| Property and equipment |
|
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|
|
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| Useful life |
|
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3 years
|
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| Related amortization expense |
|
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|
$ 1,600
|
1,400
|
$ 1,500
|
| Net book value |
$ 4,500
|
|
|
|
$ 3,300
|
|
|
|
$ 4,500
|
$ 3,300
|
|