Common Stock	9 Months Ended
Sep. 30, 2015
Text Block [Abstract]
Common Stock	Note 5 – Common Stock On March 10, 2015, the Company filed with the Securities Exchange Commission (“SEC”) an automatic shelf registration statement on Form S-3 (File No. 333-202633), which became effective upon filing, for the offer and sale of up to $100,000,000 of the Company’s common stock from time to time in at-the-market offerings under the prospectus included therein and in accordance with the Sales Agency Agreement, dated March 10, 2015, between the Company and BNY Mellon Capital Markets, LLC (the “Equity Shelf Program”). During the three months ending September 30, 2015, the Company sold, through the continuous equity offering program with BNY Mellon Capital Markets, LLC as agent, an aggregate of 272,716 shares of the Company’s common stock in the open market at a weighted average price of $54.12 per share, resulting in proceeds to the Company of $14,610,439, net of $147,579 in agent commissions. For the nine months ended September 30, 2015, the Company sold an aggregate of 645,225 shares of common stock under this program resulting in proceeds to the Company of $35,167,584, net of $355,228 in agent commissions. As of September 30, 2015, the Company had up to $64,477,188 of common stock available for sale under the program. Net proceeds from the sale of shares of common stock under the Equity Shelf Program are intended for general corporate purposes, including the acquisition of property for the construction, completion, extension or improvement of pipeline systems and facilities located in and around the communities Southwest serves. In addition, during the nine months ended September 30, 2015, the Company issued approximately 207,000 shares of common stock through the Stock Incentive Plan, Restricted Stock/Unit Plan, and Management Incentive Plan.

Note 5 – Common Stock

On March 10, 2015, the Company filed with the Securities Exchange Commission (“SEC”) an automatic shelf registration statement on Form S-3 (File No. 333-202633), which became effective upon filing, for the offer and sale of up to $100,000,000 of the Company’s common stock from time to time in at-the-market offerings under the prospectus included therein and in accordance with the Sales Agency Agreement, dated March 10, 2015, between the Company and BNY Mellon Capital Markets, LLC (the “Equity Shelf Program”). During the three months ending September 30, 2015, the Company sold, through the continuous equity offering program with BNY Mellon Capital Markets, LLC as agent, an aggregate of 272,716 shares of the Company’s common stock in the open market at a weighted average price of $54.12 per share, resulting in proceeds to the Company of $14,610,439, net of $147,579 in agent commissions. For the nine months ended September 30, 2015, the Company sold an aggregate of 645,225 shares of common stock under this program resulting in proceeds to the Company of $35,167,584, net of $355,228 in agent commissions. As of September 30, 2015, the Company had up to $64,477,188 of common stock available for sale under the program. Net proceeds from the sale of shares of common stock under the Equity Shelf Program are intended for general corporate purposes, including the acquisition of property for the construction, completion, extension or improvement of pipeline systems and facilities located in and around the communities Southwest serves.

In addition, during the nine months ended September 30, 2015, the Company issued approximately 207,000 shares of common stock through the Stock Incentive Plan, Restricted Stock/Unit Plan, and Management Incentive Plan.