Allowance for Doubtful Accounts (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Allowance For Doubtful Accounts Receivable Rollforward
Balance at beginning of year	$ 575	$ 294	$ 224
Provision charged to selling, general and administrative expenses	30	301	278
Allowance resulting from acquisitions	52	117
Write-offs, net of recoveries of amounts previously reserved	(352)	(159)	(222)
Exchange rate changes	(23)	22	14
Balance at end of year	$ 282	$ 575	$ 294