Consolidated Statements of Cash Flows (USD $)
6 Months Ended
Jun. 30, 2014
Jun. 30, 2013
Operating activities    
Net income $ 6,674,176 $ 7,099,249
Adjustments to reconcile net income to net cash provided by operating activities:    
Deferred income taxes 90,248 446,947
Noncash stock compensation expense 2,413,348 1,866,590
Increase in contingent consideration due to seller 1,305,185 413,943
Depreciation and amortization 6,366,350 5,207,779
Change in assets, net of acquisitions:    
Accounts receivable (35,434,753) (13,630,758)
Taxes receivable (payable) 2,853,605 (912,242)
Prepaid expenses and other assets (358,473) 1,013,639
Change in liabilities, net of acquisitions:    
Accounts payable 28,212,430 10,033,126
Accrued expenses and other 6,251,608 (609,406)
Net cash provided by operating activities 18,373,724 10,928,867
Investing activities    
Purchases of property and equipment (8,392,641) (4,275,673)
Payments for acquisitions, net of cash acquired (33,048,075) (1,958,236)
Net cash used in investing activities (41,440,716) (6,233,909)
Financing activities    
Principal payments on capital lease obligations 0 (15,790)
Tax benefit of stock options exercised 136,939 417,721
Payment of contingent consideration (1,524,670) (280,000)
Issuance of shares, net of issuance costs 167,360 1,029,889
Employee tax withholdings related to net share settlements of equity-based awards (853,923) (734,535)
Proceeds from Lines of Credit 5,000,000 0
Repayments of Lines of Credit (5,000,000) 0
Net cash (used in) provided by financing activities (2,074,294) 417,285
(Decrease) increase in cash and cash equivalents (25,141,286) 5,112,243
Cash and cash equivalents, beginning of period 52,506,560 41,780,984
Cash and cash equivalents, end of period 27,365,274  
Supplemental disclosure of cash flow information    
Cash paid during the period for interest 26,729 1,172
Cash paid during the period for income taxes 1,037,884 4,348,944
Contingent Earnout Payments Increase Due to New Acquisitions 880,000 0
Notes Payable, Current $ 17,507,500 $ 0