Consolidated Statements of Cash Flows (USD $)
9 Months Ended
Sep. 30, 2012
Sep. 30, 2011
Operating activities    
Net income $ 10,531,560 $ 8,516,214
Adjustments to reconcile net income to net cash provided by operating activities:    
Deferred income taxes (362,818) (142,935)
Noncash stock compensation expense 2,139,513 798,860
Reduction in contingent consideration due to seller (443,520) (246,737)
Depreciation and amortization 6,510,261 6,152,762
Change in assets, net of acquisitions:    
Accounts receivable (11,339,153) (20,704,741)
Taxes receivable (payable) 1,386,639 (651,686)
Prepaid expenses and other assets 2,293,511 2,464,595
Change in liabilities, net of acquisitions:    
Accounts payable 629,156 12,729,352
Accrued expenses and other 1,700,556 29,103
Net cash provided by operating activities 13,045,705 8,944,787
Investing activities    
Purchases of property and equipment (6,833,816) (4,898,060)
Payments for acquisitions, net of cash acquired (3,601,483) (2,819,829)
Net cash used in investing activities (10,435,299) (7,717,889)
Financing activities    
Principal payments on capital lease obligations (155,849) (197,765)
Tax benefit of stock options exercised 360,443 152,897
Payment of contingent consideration (2,882,500) (1,000,000)
Issuance of shares, net of issuance costs 1,420,560 790,189
Employee tax withholdings related to net share settlements of equity-based awards (192,736) 0
Net cash used in financing activities (1,450,082) (254,679)
Increase in cash and cash equivalents 1,160,324 972,219
Cash and cash equivalents, beginning of period 47,007,309 43,218,164
Cash and cash equivalents, end of period 48,167,633 44,190,383
Supplemental disclosure of cash flow information    
Cash paid during the period for interest 8,290 18,229
Cash paid during the period for income taxes 5,092,160 5,750,100
Non-cash financing activity    
Vesting of restricted shares 37,850 0
Due to seller $ 631,914 $ 3,869,624