Stockholders’ equity Stockholders' Equity (Notes) - USD ($)
$ / shares in Units, $ in Thousands

1 Months Ended

12 Months Ended

Aug. 05, 2019

Mar. 16, 2018

Sep. 30, 2019

Jul. 31, 2019

Jun. 30, 2019

Jan. 31, 2019

Dec. 31, 2018

Dec. 31, 2019

Dec. 31, 2018

Dec. 31, 2017

Dec. 31, 2016

Mar. 31, 2016

Equity [Abstract]

Stockholders' Equity Note Disclosure [Text Block]

Common Stock

Pursuant to the Company’s amended and restated certificate of incorporation (“Certificate of Incorporation”), the Company is authorized to issue up to 100,000,000 shares of common stock, par value $0.01 per share. As of December 31, 2019, there were 50,879,949 shares of common stock issued and 50,488,010 outstanding.

On March 16, 2018, 20,000 shares of common stock were issued as additional consideration for the investment in Challenger upon resolution of terms for such holdback shares.

Preferred Stock

Pursuant to the Company’s Certificate of Incorporation, the Company is authorized to issue up to 5,000,000 shares of preferred stock, par value $0.01 per share. The Board of Directors (the “BOD”) has the authority, subject to any limitations imposed by law or Nasdaq rules, without further action by the stockholders, to issue such preferred stock in one or more series and to fix the voting powers (if any), the preferences and relative, participating, optional or other special rights or privileges, if any, of such series and the qualifications, limitations or restrictions thereof. These rights, preferences and privileges may include, but are not limited to, dividend rights, conversion rights, voting rights, terms of redemption, liquidation preferences, sinking fund terms and the number of shares constituting any series or the designation of that series. As of December 31, 2019, there were no shares of preferred stock issued and outstanding.

Share Repurchase Programs

In March 2016, the Company’s BOD authorized a share repurchase program of up to 1,000,000 shares of its common stock through 2017. The share repurchase program expired in 2017. No shares were repurchased during the year ended December 31, 2017.

In October 2018, the Company’s BOD authorized a share repurchase program for the period beginning on October 3, 2018 and ending on October 3, 2020 of the Company’s common stock for an aggregate price not to exceed $30.0 million. The timing, volume and nature of share repurchases are at the discretion of management and dependent on market conditions, corporate and regulatory requirements, available cash and other factors, and may be suspended or discontinued at any time. Authorized repurchases may be made from time to time in the open market, through block trades or in privately negotiated transactions. No assurance can be given that any particular amount of common stock will be repurchased. All or part of the repurchases may be implemented under a trading plan under Rule 10b5-1 or Rule 10b-18 established by the SEC, which would allow repurchases under pre-set terms at times when the Company might otherwise be prevented from doing so under insider trading laws or because of self-imposed blackout periods. This repurchase program may be modified, extended or terminated by the BOD at any time. The Company intends to finance any repurchases with available cash and proceeds from borrowings under lines of credit.

In December 2018, the Company repurchased 136,756 shares for approximately $1.0 million.

On December 31, 2018, the Company’s BOD authorized implementation of share repurchases in accordance with a trading plan under Rule 10b5-1 (the “December 2018 Trading Plan”) within the 2018 Share Repurchase Program. The trading plan was effective from January 2, 2019 until March 30, 2019. In January 2019, the Company repurchased 7,862 shares for approximately $0.1 million under the December 2018 Trading Plan.

In June 2019, the Company’s BOD authorized discrete repurchases under the 2018 Share Repurchase Program of 39,320 shares for approximately $0.3 million.

On June 27, 2019, the Company’s BOD authorized implementation of share repurchases in accordance with a trading plan under Rule 10b5-1 (the “June 2019 Trading Plan”) within the 2018 Share Repurchase Program. The trading plan was effective from July 1, 2019 until August 5, 2019. In July 2019, the Company repurchased 144,584 shares for approximately $1.2 million under the June 2019 Trading Plan.

In September 2019, the Company’s BOD authorized discrete repurchases under the 2018 Share Repurchase Program of 63,417 shares for approximately $0.6 million.

As of December 31, 2019, the remaining dollar value of shares that may yet be purchased under the 2018 Share Repurchase Program was $26.8 million.

Class of Stock [Line Items]