Stockholders' Equity	12 Months Ended
Dec. 31, 2017
Stockholders' Equity Note [Abstract]
Stockholders' Equity	STOCKHOLDERS’ EQUITY Share Repurchase Plan Under the terms of its Credit Facility, the Company is authorized to purchase up to $40.0 million of shares of its common stock in open market purchases on an annual basis, subject to board of director authorization. In October 2016, the Company’s board of directors authorized the open market repurchase of up to $40.0 million of our common stock to be made during 2017. The Company repurchased shares under this program throughout 2017. In October 2017, the Company’s board of directors authorized a similar $40.0 million program for 2018. On February 27, 2018, the Company amended its Credit Facility, which limits the open market share repurchases to $30.0 million for 2018 (see Note 15). Once repurchased, the Company promptly retires such shares. The Company is also authorized to repurchase up to $10.0 million of the Company’s common stock in each calendar year in connection with the Company’s equity compensation programs for employees. The participants in the Company’s equity plans may surrender shares of common stock in satisfaction of tax obligations arising from the vesting of restricted stock and restricted stock unit awards under such plans and in connection with the exercise of stock option awards. The deemed price paid is the closing price of the Company’s common stock on The Nasdaq Global Select Market on the date that the restricted stock or restricted stock unit vests or the shares of the Company’s common stock are surrendered in exchange for stock option exercises. With regard to stock option awards, the option holder may elect a “net, net” exercise in connection with the exercise of employee stock options such that the option holder receives a number of shares equal to the built-in gain in the option shares divided by the market price of the Company’s common stock on the date of exercise, less a number of shares equal to the taxes due upon the exercise of the option divided by the market price of the Company’s common stock on the date of exercise. The shares of Company common stock surrendered to the Company for taxes due on the exercise of the option are deemed repurchased by the Company. During 2017, the Company acquired 1,599,093 shares of the Company’s common stock for $35.3 million ($22.10 average price per share) through the open market repurchase programs discussed above and 112,899 shares of the Company’s common stock for $2.5 million ($22.15 average price per share) in connection with the satisfaction of tax obligations in connection with the vesting of restricted stock and restricted stock units. Once repurchased, the Company immediately retired all such shares. During 2017, the Company did not acquire any of the Company’s common stock in connection with “net, net” exercises of employee stock options. During 2016, the Company acquired 2,226,875 shares of the Company’s common stock for $41.8 million ($18.76 average price per share) through open market repurchase programs and 61,039 shares of the Company’s common stock for $1.2 million ($19.65 average price per share) in connection with the satisfaction of tax obligations in connection with the vesting of restricted stock and restricted stock units. In addition, during 2016, the Company acquired 61,980 shares of the Company’s common stock in connection with “net, net” exercises of employee stock options for a gross value of $1.5 million ($1.2 million in cash value). Once repurchased, the Company immediately retired all such shares. During 2015, the Company acquired 1,306,199 shares of the Company’s common stock for $24.3 million ($18.58 average price per share) through open market repurchase programs and 32,902 shares of the Company’s common stock for $0.6 million ($17.05 average price per share) in connection with the satisfaction of tax obligations in connection with the vesting of restricted stock, the exercise of stock options and the distribution of deferred stock units. In addition, during 2015, the Company acquired 163,500 shares of the Company’s common stock in connection with “net, net” exercises of employee stock options for a gross value of $3.0 million ($0.9 million in cash value). Once repurchased, the Company immediately retired all such shares. Equity-Based Compensation Plans Employee Plans In April 2016, the Company’s stockholders approved the 2016 Employee Equity Incentive Plan, which was amended in 2017 by the First Amendment to the 2016 Employee Equity Incentive Plan (as amended, the “2016 Employee Plan”). The 2016 Employee Plan replaced the 2013 Employee Equity Incentive Plan. The 2016 Employee Plan provides for equity-based compensation awards, including restricted shares of common stock, performance awards, stock options, stock units and stock appreciation rights. There are 2,132,739 shares of the Company’s common stock registered for issuance under the 2016 Employee Plan. The 2016 Employee Plan is administered by the Compensation Committee of the Board of Directors, which determines eligibility, timing, pricing, amount and other terms or conditions of awards. At December 31, 2017, there were no options and 448,225 unvested restricted stock units outstanding under the 2016 Employee Plan. Prior to the 2016 Employee Plan, the Board of Directors administered the 2013 Employee Equity Incentive Plan (the “2013 Employee Plan”) and the 2009 Employee Equity Incentive Plan (the “2009 Employee Plan”). At December 31, 2017, there were no options and 980,653 unvested shares of restricted stock and restricted stock units outstanding under the 2013 Employee Plan, and 126,680 options and no unvested shares of restricted stock and restricted stock units outstanding under the 2009 Employee Plan. Director Plans In April 2016, the Company’s stockholders also approved the 2016 Director Equity Incentive Plan (the “2016 Director Plan”), which replaced the 2011 Non-Employee Director Equity Incentive Plan. The 2016 Director Plan provides for equity-based compensation awards, including non-qualified stock options and stock units. The Board of Directors administers the 2016 Director Plan and has the authority to establish, amend and rescind any rules and regulations related to the 2016 Director Plan. There are 166,456 shares of the Company’s common stock registered for issuance under the 2016 Director Plan. At December 31, 2017, there were 49,195 deferred stock units outstanding under the 2016 Director Plan. Prior to the 2016 Director Plan, the Board of Directors administered the 2011 Non-Employee Director Equity Plan (“2011 Director Plan”), the 2006 Non-Employee Director Equity Plan (“2006 Director Plan”) and the 2001 Non-Employee Director Equity Plan (“2001 Director Plan”), all of which contained substantially the same provisions as the current plan. At December 31, 2017, there were 119,366 deferred stock units outstanding under the 2011 Director Plan, 46,841 deferred stock units outstanding under the 2006 Director Plan and 54,575 deferred stock units outstanding under the 2001 Director Equity Plan. Activity and related expense associated with these plans are described in Note 9.

STOCKHOLDERS’ EQUITY

Share Repurchase Plan

Under the terms of its Credit Facility, the Company is authorized to purchase up to $40.0 million of shares of its common stock in open market purchases on an annual basis, subject to board of director authorization. In October 2016, the Company’s board of directors authorized the open market repurchase of up to $40.0 million of our common stock to be made during 2017. The Company repurchased shares under this program throughout 2017. In October 2017, the Company’s board of directors authorized a similar $40.0 million program for 2018. On February 27, 2018, the Company amended its Credit Facility, which limits the open market share repurchases to $30.0 million for 2018 (see Note 15). Once repurchased, the Company promptly retires such shares.

The Company is also authorized to repurchase up to $10.0 million of the Company’s common stock in each calendar year in connection with the Company’s equity compensation programs for employees. The participants in the Company’s equity plans may surrender shares of common stock in satisfaction of tax obligations arising from the vesting of restricted stock and restricted stock unit awards under such plans and in connection with the exercise of stock option awards. The deemed price paid is the closing price of the Company’s common stock on The Nasdaq Global Select Market on the date that the restricted stock or restricted stock unit vests or the shares of the Company’s common stock are surrendered in exchange for stock option exercises. With regard to stock option awards, the option holder may elect a “net, net” exercise in connection with the exercise of employee stock options such that the option holder receives a number of shares equal to the built-in gain in the option shares divided by the market price of the Company’s common stock on the date of exercise, less a number of shares equal to the taxes due upon the exercise of the option divided by the market price of the Company’s common stock on the date of exercise. The shares of Company common stock surrendered to the Company for taxes due on the exercise of the option are deemed repurchased by the Company.

During 2017, the Company acquired 1,599,093 shares of the Company’s common stock for $35.3 million ($22.10 average price per share) through the open market repurchase programs discussed above and 112,899 shares of the Company’s common stock for $2.5 million ($22.15 average price per share) in connection with the satisfaction of tax obligations in connection with the vesting of restricted stock and restricted stock units. Once repurchased, the Company immediately retired all such shares. During 2017, the Company did not acquire any of the Company’s common stock in connection with “net, net” exercises of employee stock options.

During 2016, the Company acquired 2,226,875 shares of the Company’s common stock for $41.8 million ($18.76 average price per share) through open market repurchase programs and 61,039 shares of the Company’s common stock for $1.2 million ($19.65 average price per share) in connection with the satisfaction of tax obligations in connection with the vesting of restricted stock and restricted stock units. In addition, during 2016, the Company acquired 61,980 shares of the Company’s common stock in connection with “net, net” exercises of employee stock options for a gross value of $1.5 million ($1.2 million in cash value). Once repurchased, the Company immediately retired all such shares.

During 2015, the Company acquired 1,306,199 shares of the Company’s common stock for $24.3 million ($18.58 average price per share) through open market repurchase programs and 32,902 shares of the Company’s common stock for $0.6 million ($17.05 average price per share) in connection with the satisfaction of tax obligations in connection with the vesting of restricted stock, the exercise of stock options and the distribution of deferred stock units. In addition, during 2015, the Company acquired 163,500 shares of the Company’s common stock in connection with “net, net” exercises of employee stock options for a gross value of $3.0 million ($0.9 million in cash value). Once repurchased, the Company immediately retired all such shares.

Equity-Based Compensation Plans

Employee Plans

In April 2016, the Company’s stockholders approved the 2016 Employee Equity Incentive Plan, which was amended in 2017 by the First Amendment to the 2016 Employee Equity Incentive Plan (as amended, the “2016 Employee Plan”). The 2016 Employee Plan replaced the 2013 Employee Equity Incentive Plan. The 2016 Employee Plan provides for equity-based compensation awards, including restricted shares of common stock, performance awards, stock options, stock units and stock appreciation rights. There are 2,132,739 shares of the Company’s common stock registered for issuance under the 2016 Employee Plan. The 2016 Employee Plan is administered by the Compensation Committee of the Board of Directors, which determines eligibility, timing, pricing, amount and other terms or conditions of awards. At December 31, 2017, there were no options and 448,225 unvested restricted stock units outstanding under the 2016 Employee Plan.

Prior to the 2016 Employee Plan, the Board of Directors administered the 2013 Employee Equity Incentive Plan (the “2013 Employee Plan”) and the 2009 Employee Equity Incentive Plan (the “2009 Employee Plan”). At December 31, 2017, there were no options and 980,653 unvested shares of restricted stock and restricted stock units outstanding under the 2013 Employee Plan, and 126,680 options and no unvested shares of restricted stock and restricted stock units outstanding under the 2009 Employee Plan.

Director Plans

In April 2016, the Company’s stockholders also approved the 2016 Director Equity Incentive Plan (the “2016 Director Plan”), which replaced the 2011 Non-Employee Director Equity Incentive Plan. The 2016 Director Plan provides for equity-based compensation awards, including non-qualified stock options and stock units. The Board of Directors administers the 2016 Director Plan and has the authority to establish, amend and rescind any rules and regulations related to the 2016 Director Plan. There are 166,456 shares of the Company’s common stock registered for issuance under the 2016 Director Plan. At December 31, 2017, there were 49,195 deferred stock units outstanding under the 2016 Director Plan.

Prior to the 2016 Director Plan, the Board of Directors administered the 2011 Non-Employee Director Equity Plan (“2011 Director Plan”), the 2006 Non-Employee Director Equity Plan (“2006 Director Plan”) and the 2001 Non-Employee Director Equity Plan (“2001 Director Plan”), all of which contained substantially the same provisions as the current plan. At December 31, 2017, there were 119,366 deferred stock units outstanding under the 2011 Director Plan, 46,841 deferred stock units outstanding under the 2006 Director Plan and 54,575 deferred stock units outstanding under the 2001 Director Equity Plan.

Activity and related expense associated with these plans are described in Note 9.