Segment Information (Narrative) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues from customers	$ 31,382	$ 31,527	$ 31,003	$ 31,105	$ 29,746	$ 28,527	$ 26,901	$ 24,721	$ 125,017	$ 109,895	$ 87,973
Threshold percentage of total revenues required for major customer classification									10.00%
United States [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues from customers									$ 69,778	$ 60,195	$ 51,695