Consolidated Statements of Cash Flows (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Cash flows from operating activities:
Net income	$ 48,996	$ 37,530	$ 25,871
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	18,490	11,108	5,628
Gain on disposal of buildings and equipment	(1,343)	(954)	(362)
Share-based compensation	1,503	659	524
Provision for bad debts	2,934	1,083	1,186
Excess tax benefit on share-based compensation	(4,297)	0	0
Deferred tax provision	8,280	10,145	14,491
Changes in (net of acquisitions):
Accounts receivable	(28,891)	(6,276)	(14,656)
Prepaid expenses and other assets	(6,205)	(8,550)	(5,521)
Accounts payable	(380)	(5,587)	8,356
Accrued expenses and other liabilities	(2,964)	(2,435)	(2,353)
Net cash provided by operating activities	36,123	36,723	33,164
Cash flows from investing activities:
Acquisition of business, net of cash acquired	(100,648)	(88,977)	(131,290)
Capital expenditures	(31,546)	(15,140)	(10,105)
Proceeds from sale of buildings and equipment	5,121	510	865
Net cash used in investing activities	(127,073)	(103,607)	(140,530)
Cash flows from financing activities:
Borrowings under revolving credit facilities	130,441	141,115	124,081
Payments under revolving credit facilities	(108,426)	(141,115)	(144,581)
Long-term debt borrowings	22,000	40,500	140,000
Long-term debt payments	(12,875)	(15,500)	(3,500)
Debt issuance cost	(1,541)	(2,220)	(4,183)
Payments of contingent earnouts	(2,407)	(83)	(2,553)
Proceeds from issuance of common stock (net of issuance costs)	53,059	57,119	869
Redemption of mandatory redeemable preferred stock	0	(5,000)	0
Excess tax benefit on share-based compensation	4,297	818	0
Reduction of capital lease obligation	(68)	(157)	(448)
Net cash provided by financing activities	84,480	75,477	109,685
Net (decrease) increase in cash and cash equivalents	(6,470)	8,593	2,319
Cash and cash equivalents:
Beginning of period	11,908	3,315	996
End of period	5,438	11,908	3,315
Supplemental cash flow information:
Cash paid for interest	6,505	8,214	3,517
Cash paid for income taxes (net of refunds)	19,081	13,961	1,127
Noncash contingent earnout	4,288	17,733	2,581
Capital expenditures (non-cash)	0	1,749	0
Noncash issuance of common stock for acquisition	$ 0	$ 0	$ 3,000