CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $) In Thousands, unless otherwise specified	9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012
Cash flows from operating activities:
Net income	$ 32,869	$ 22,778
Adjustments to reconcile net income to cash provided by operating activities:
Depreciation and amortization	25,535	25,208
Amortization of discount and deferred debt issuance costs	2,612	2,091
Share-based compensation	2,376	2,945
Deferred income taxes, net	1,480	1,622
Provision for losses on accounts receivable	4,430	4,237
Loss on extinguishment of debt, net of original issue discount paid		6,400
Loss on sale of assets	81	76
Changes in operating assets and liabilities	(13,935)	(23,102)
Cash provided by operating activities	55,448	42,255
Cash flows from investing activities:
Purchases of property and equipment	(15,007)	(11,324)
Acquisitions of businesses, net of cash acquired	(19,995)	(22,077)
Proceeds from sale of assets	344	80
Cash used in investing activities	(34,658)	(33,321)
Cash flows from financing activities:
Long-term debt repayments	(14,190)	(172,077)
Long-term debt borrowings		175,000
Payments on obligations under capital leases	(5,446)	(4,510)
Debt issuance costs	(2)	(4,007)
Cash used in financing activities	(19,638)	(5,594)
Effect of exchange rate changes on cash and cash equivalents	(96)	93
Increase in cash and cash equivalents	1,056	3,433
Cash and cash equivalents at beginning of period	50,134	25,651
Cash and cash equivalents at end of period	51,190	29,084
Supplemental schedule of non-cash investing and financing activities:
Notes issued in connection with acquisitions	1,336	739
Capital lease obligations	8,409	4,254
Settlement of Seller obligations in connection with an acquisition	$ 1,240