Consolidated Statements of Cash Flows (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Cash flows from operating activities:
Net income	$ 27,098	$ 23,756	$ 22,688
Adjustments to reconcile net income to net cash provided by operating activities:
Income tax benefit on reduction of uncertain tax position liabilities	0	0	(1,602)
Loss (gain) on change in fair value of contingent consideration, net	(1,392)	(1,676)	789
Depreciation and amortization	9,758	8,617	7,971
Non-cash compensation expense	4,823	3,673	3,615
Deferred income taxes	(113)	(285)	716
Changes in other operating items, net of acquired amounts:
Accounts and other receivables	(6,024)	(9,158)	(11,262)
Costs and estimated earnings in excess of billings on uncompleted contracts	(8,291)	(4,941)	(1,256)
Prepaid expenses and other current assets	(1,967)	(2,807)	(1,227)
Accounts payable and accrued expenses	8,794	1,174	4,003
Billings in excess of costs and estimated earnings on uncompleted contracts	1,416	(1,478)	3,218
Income tax benefit from stock-based compensation	(2,506)	(359)	(2,034)
Contingent consideration payments in excess of fair value on acquisition date	(1,043)	(708)	(602)
Other	445	445	295
Net cash provided by operating activities	30,998	16,253	25,312
Cash flows from investing activities:
Additions to property, plant and equipment	(2,757)	(6,714)	(2,536)
Acquisitions, net of cash acquired	(8,670)	(13,505)	(12,184)
Other investing activities	246	0	0
Net cash used in investing activities	(11,181)	(20,219)	(14,720)
Cash flows from financing activities:
Short-term borrowings	20,392	407	0
Proceeds from long-term debt	40,000	0	0
Repayment of long-term debt	(2,223)	0	0
Contingent consideration payments	(977)	(1,026)	(1,263)
Change in negative cash book balance	(440)	5,261	(1,888)
Repurchases of common stock	(66,640)	(1,747)	(3,433)
Income tax benefit from stock-based compensation	2,506	359	2,034
Tax withholding payments for employee stock-based compensation in exchange for shares surrendered	(3,407)	(623)	(2,750)
Proceeds from issuance of common stock	102	63	284
Other financing activities	(5)	(6)	(126)
Net cash provided by (used in) financing activities	(10,692)	2,688	(7,142)
Effect of exchange rate changes on cash and cash equivalents	(231)	(836)	160
Net change in cash and cash equivalents	8,894	(2,114)	3,610
Cash and cash equivalents at beginning of year	5,647	7,761	4,151
Cash and cash equivalents at end of year	14,541	5,647	7,761
Cash paid during the year for:
Interest	583	179	104
Income taxes	17,439	13,879	12,532
Non-cash investing and financing activities:
Accrued contingent consideration	$ 5,345	$ 4,243	$ 765