Schedule II Valuation and Qualifying Accounts - Schedule of Valuation and Qualifying Accounts (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Allowance for Doubtful Accounts [Member]
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Period	$ 657	$ 1,329	$ 727
Charged to Cost and Expenses	941	244	741
Credited to Other Accounts	(65)	(67)	(57)
Amount Written Off	(165)	(849)	(82)
Balance at End of Period	1,368	657	1,329
Accounts Receivable [Member]
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Period	490	722	443
Charged to Cost and Expenses	941	195	316
Credited to Other Accounts	(60)	(67)	(57)
Amount Written Off	(165)	(360)	20
Balance at End of Period	1,206	490	722
Investment in Sales-Type Leases [Member]
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Period	167	607	284
Charged to Cost and Expenses	0	49	425
Credited to Other Accounts	(5)	0	0
Amount Written Off	0	(489)	(102)
Balance at End of Period	$ 162	$ 167	$ 607