Common Stock	12 Months Ended
Dec. 31, 2017
Equity [Abstract]
Common Stock	Common Stock Common Stock and Rights Agreement The Company has Common Stock and also Common Share Purchase Rights that trade with the Common Stock. The Common Share Purchase Rights were issued pursuant to the shareholder rights plan discussed below. On February 15, 2008, the Board of Directors of the Company adopted a shareholder rights plan and declared a dividend of one Common Share Purchase Right for each outstanding share of Common Stock of the Company payable to the shareholders of record on May 26, 2008. The plan was effective as of May 27, 2008. Each right entitles the registered holder to purchase from the Company one share of Common Stock at a price of $100.00 per share, subject to adjustment. Subject to certain conditions, the rights are redeemable by the Company and are exchangeable for shares of Common Stock at a favorable price. The rights have no voting power and unless the rights are redeemed, exchanged or terminated earlier, they will expire on May 26, 2018. The rights are an embedded feature of the Company’s Common Stock and not a free-standing instrument, and therefore, do not require separate accounting treatment. On August 12, 2016, the Company announced a 2-for-1 stock split in the form of a 100% stock dividend payable on September 15, 2016 to shareholders of record at the close of business on August 31, 2016. In this report, all per share amounts and number of shares have been restated to reflect the stock split for all periods presented except for the total authorized shares which was 40 million both before and after the stock split. Stock Options Stock options to purchase 55,223 shares of the Company's Stock in 2017, 91,330 shares in 2016 and 95,144 shares in 2015 were not included in the computation of dilutive securities because their inclusion would have been anti-dilutive.

Common Stock

Common Stock and Rights Agreement

The Company has Common Stock and also Common Share Purchase Rights that trade with the Common Stock. The Common Share Purchase Rights were issued pursuant to the shareholder rights plan discussed below.

On February 15, 2008, the Board of Directors of the Company adopted a shareholder rights plan and declared a dividend of one Common Share Purchase Right for each outstanding share of Common Stock of the Company payable to the shareholders of record on May 26, 2008. The plan was effective as of May 27, 2008. Each right entitles the registered holder to purchase from the Company one share of Common Stock at a price of $100.00 per share, subject to adjustment. Subject to certain conditions, the rights are redeemable by the Company and are exchangeable for shares of Common Stock at a favorable price. The rights have no voting power and unless the rights are redeemed, exchanged or terminated earlier, they will expire on May 26, 2018. The rights are an embedded feature of the Company’s Common Stock and not a free-standing instrument, and therefore, do not require separate accounting treatment.

On August 12, 2016, the Company announced a 2-for-1 stock split in the form of a 100% stock dividend payable on September 15, 2016 to shareholders of record at the close of business on August 31, 2016. In this report, all per share amounts and number of shares have been restated to reflect the stock split for all periods presented except for the total authorized shares which was 40 million both before and after the stock split.

Stock Options

Stock options to purchase 55,223 shares of the Company's Stock in 2017, 91,330 shares in 2016 and 95,144 shares in 2015 were not included in the computation of dilutive securities because their inclusion would have been anti-dilutive.