Changes in the Company's carrying value of goodwill by reporting segment (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Goodwill [Line Items]
Document Period End Date	Dec. 31, 2013
Goodwill [Roll Forward]
Goodwill, Gross, Period Start	$ 100,536	$ 98,977
Accumulated Impairment Loss	(37,273)	(38,527)	(37,450)
Additions	0	0
Goodwill, Translation and Purchase Accounting Adjustments	271	482
Goodwill, Gross, End of Period	99,553	100,536
GETS [Member]
Goodwill [Roll Forward]
Goodwill, Gross, Period Start	35,713	35,713
Accumulated Impairment Loss	(164)	(164)	(164)
Additions	0	0
Goodwill, Translation and Purchase Accounting Adjustments	0	0
Goodwill, Gross, End of Period	35,713	35,713
PSS [Member]
Goodwill [Roll Forward]
Goodwill, Gross, Period Start	48,245	47,019
Accumulated Impairment Loss	(30,057)	(31,448)	(30,616)
Additions	0	0
Goodwill, Translation and Purchase Accounting Adjustments	221	394
Goodwill, Gross, End of Period	47,075	48,245
MRI [Member]
Goodwill [Roll Forward]
Goodwill, Gross, Period Start	16,578	16,245
Accumulated Impairment Loss	(7,052)	(6,915)	(6,670)
Additions	0	0
Goodwill, Translation and Purchase Accounting Adjustments	50	88
Goodwill, Gross, End of Period	$ 16,765	$ 16,578