Business Acquisition (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2015	Dec. 31, 2014
Business Acquisition [Line Items]
Goodwill	$ 30,867	$ 31,995
Telestack Limited [Member]
Business Acquisition [Line Items]
Date of acquisition	Apr. 01, 2014
Percentages of stock acquired of Telestack Limited (in hundredths)	100.00%
Total purchase price	36,183
Decrease in purchase price	178
Purchase price deposited in escrow	2,500
Period of time for amount held in escrow	1 year
Goodwill	18,078
Other intangibles assets	$ 14,445
Telestack Limited [Member] | Trade names [Member]
Business Acquisition [Line Items]
Useful life of intangible assets	15 years
Telestack Limited [Member] | Patents [Member] | Minimum [Member]
Business Acquisition [Line Items]
Useful life of intangible assets	5 years
Telestack Limited [Member] | Patents [Member] | Maximum [Member]
Business Acquisition [Line Items]
Useful life of intangible assets	10 years
Telestack Limited [Member] | Noncompete agreements [Member]
Business Acquisition [Line Items]
Useful life of intangible assets	3 years
Telestack Limited [Member] | Customer relationships [Member]
Business Acquisition [Line Items]
Useful life of intangible assets	11 years