Detail of Certain Balance Sheet Accounts (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Activity in allowance for doubtful accounts
Balance at beginning of year	$ 6,333	$ 4,615	$ 5,029
Additions for bad debt expense	19	2,753	214
Deductions for uncollectible receivables written off, net of recoveries	(1,892)	(1,090)	(770)
Allowance for doubtful accounts of acquired companies at date of acquisition		55	142
Balance at end of year	4,460	6,333	4,615
Other current liabilities
Accrued warranty costs	6,795	6,781
Accrued job losses	758	2,137
Accrued rent and lease obligations	673	673
Accrued sales and use tax	1,821	1,710
Deferred revenue	1,320	1,143
Liabilities due to former owners	4,054	2,349
Other current liabilities	12,747	12,284
Total other current liabilities	$ 28,168	$ 27,077