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Disposition of Assets (Narrative) (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014	Dec. 31, 2014	Dec. 31, 2013
Income Statement [Abstract]
Proceeds from sale of subsidiary	$ 0	$ 1,121
Loss on sale of subsidiary	0us-gaap_GainLossOnSaleOfBusiness	596us-gaap_GainLossOnSaleOfBusiness
Loss from discontinued operation, net of income taxes	(355)	(2,041)
From discontinued operation (in US dollars per share)	$ 0.00	$ (0.03)
Restructuring reserve	239us-gaap_RestructuringReserve	324us-gaap_RestructuringReserve	281us-gaap_RestructuringReserve	194us-gaap_RestructuringReserve
United Kingdom Construction [Member]
Income Statement [Abstract]
Revenues	276	8,846
Loss from discontinued operation, net of income taxes	(355)	(2,041)
From discontinued operation (in US dollars per share)	$ 0.00	$ (0.03)
Restructuring reserve	1,100
Assets of discontinued operation:
Current assets	4,198		6,265
Non-current assets	138		278
Liabilities of discontinued operation:
Current liabilities	9,014		10,743
Non-current liabilities	43		94
United States Building Services [Member] \| United States Building Services Subsidiary [Member]
Income Statement [Abstract]
Proceeds from sale of subsidiary		1,100
Selling, General and Administrative Expenses [Member] \| United States Building Services [Member] \| United States Building Services Subsidiary [Member]
Income Statement [Abstract]
Loss on sale of subsidiary		$ 600