Consolidated Statements of Cash Flows (Unaudited) - USD ($)
9 Months Ended
Sep. 30, 2016
Sep. 30, 2015
Operating activities    
Net income $ 4,555,430 $ 6,104,854
Adjustments to reconcile net income to net cash provided by operating activities:    
Deferred income taxes 2,739,830 (1,714,478)
Noncash stock compensation expense 11,158,738 9,211,324
Noncash interest expense 5,669,403 3,031,114
Change in contingent consideration due to seller (102,954) 145,938
Change in contingent consideration due from seller 31,025 0
Depreciation and amortization 23,670,711 16,572,233
Change in assets, net of acquisitions:    
Accounts receivable (49,504,213) (17,535,896)
Income taxes receivable (4,937,428) 1,037,805
Prepaid expenses and other assets (415,260) 128,630
Change in liabilities, net of acquisitions:    
Accounts payable 41,696,285 31,501,579
Accrued expenses and other liabilities 20,549,995 4,313,420
Net cash provided by operating activities 55,111,562 52,796,523
Investing activities    
Purchases of property and equipment (37,248,736) (10,006,874)
Payments for acquisitions, net of cash acquired 0 (390,538,011)
Net cash used in investing activities (37,248,736) (400,544,885)
Financing activities    
Tax benefit of stock options exercised 1,233,866 1,684,155
Receipt of contingent consideration due from seller 750,000 0
Payments of contingent consideration due to seller (2,273,743) (2,945,833)
Proceeds from exercise of stock options 754,739 1,017,207
Employee tax withholdings related to net share settlements of equity-based awards (4,679,014) (1,632,795)
Purchases of treasury stock (35,960,073) 0
Proceeds from borrowing on line of credit 0 34,782,500
Repayments of amounts borrowed on line of credit 0 (34,782,500)
Proceeds from borrowing on ABL facility 23,500,000 35,000,000
Repayments of amounts borrowed on ABL facility (23,500,000) (35,000,000)
Proceeds from sale of common stock, net of underwriting discounts and commissions 0 158,412,500
Proceeds from issuance of convertible notes, net of underwriting discounts and commissions 0 223,100,000
Payment of common stock and debt issuance costs 0 (4,133,851)
Payment to former owners of One Stop Logistics 0 (17,507,500)
Net cash (used in) provided by financing activities (40,174,225) 357,993,883
(Decrease) Increase in cash and cash equivalents (22,311,399) 10,245,521
Cash and cash equivalents, beginning of period 56,522,194 32,542,119
Cash and cash equivalents, end of period 34,210,795 42,787,640
Supplemental disclosure of cash flow information    
Cash paid during the year for interest 3,793,821 2,439,991
Cash paid for income taxes 2,808,772 1,868,942
Noncash investing activity    
Issuance of common stock in connection with Command acquisition 0 14,746,000
Noncash financing activity    
Fair value of due to seller obligation at acquisition date 0 1,500,000
Liability for purchases of treasury stock not yet settled $ 510,999 $ 0