| **Common Stock**                                                            | 9 Months Ended                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                           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| **Stockholders' Equity Note [Abstract]**                                    |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                         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| Disclosure of Compensation Related Costs, Share-based Payments [Text Block] | COMMON STOCKSale of Equity Securities In May 2012, we completed a public offering of 6,500,000 shares of our common stock, par value $0.01 per share, at an offering price of $26.50 per share. Net proceeds of the offering were approximately $164.5 million, after deducting underwriting discounts and commissions and offering expenses, of which $65,000 is included in common shares-par value and $164.4 million is included in additional paid-in capital ("APIC") on the balance sheet. We used the net proceeds from the offering to finance a portion of the Merit Acquisition and for general corporate purposes. The offering was made pursuant to an effective shelf registration statement on Form S-3 filed with the SEC on January 23, 2012.    Stock-Based Compensation PlansThe following table provides a summary of the impact of our outstanding stock-based compensation plans on the results of operations for the periods presented:  Three Months Ended September 30, Nine Months Ended September 30,  2012 2011 2012 2011 (1)  (in thousands)         Stock-based compensation expense $2,225 $1,693 $6,126 $7,242Income tax benefit (847) (643) (2,333) (2,751)Net expense $1,378 $1,050 $3,793 $4,491         __________ (1) Includes a total of $2.5 million, pretax, related to a separation agreement with our former chief executive officer.Stock Appreciation Rights ("SARs")The SARs vest ratably over a three-year period and may be exercised at any point after vesting through 10 years from the date of issuance. Pursuant to the terms of the awards, upon exercise, the executive officers will receive, in shares of common stock, the excess of the market price of the award on the date of exercise over the market price of the award on the date of issuance.     In January 2012, the Compensation Committee of our Board of Directors (the "Committee") awarded 68,361 SARs to our executive officers. The fair value of each SAR award was estimated on the date of grant using a Black-Scholes pricing model using the following assumptions:  Nine Months Ended September 30, 2012 2011    Expected term6 years 6 yearsRisk-free interest rate1.1% 2.5%Expected volatility64.3% 60.2%Weighted-average grant date fair value per share$17.61 $25.22    The expected term of the award was estimated using historical stock option exercise behavior data. The risk-free interest rate was based on the U.S. Treasury yields approximating the expected life of the award in effect at the time of grant. The expected volatility was based on our historical volatility. We do not expect to declare or pay dividends in the foreseeable future.The following table presents the changes in our SARs:  Nine Months Ended September 30,  2012 2011  NumberofSARs Weighted                 -AverageExercisePrice Average Remaining ContractualTerm(in years) Aggregate IntrinsicValue(in thousands) NumberofSARs Weighted                 -AverageExercisePrice Average Remaining ContractualTerm(in years) Aggregate IntrinsicValue(in thousands)                 Outstanding beginning of year, January 1, 50,471 $31.61 8.6 $341 57,282 $24.44 9.3 $—Granted 68,361 30.19 9.3 — 31,552 43.95 9.7 —Exercised — — — — (2,814) 24.44 — —Forfeited — — — — (35,549) 31.57 — —Outstanding at September 30, 118,832 30.80 8.7 328 50,471 31.61 8.9 —Vested and expected to vest at September 30, 113,426 30.77 8.7 319 46,488 31.45 8.9 —Exercisable at September 30, 27,458 28.84 7.8 153 10,636 24.44 8.6 —                 The total compensation cost related to SARs granted and not yet recognized in our statement of operations as of September 30, 2012 was $1.2 million. The cost is expected to be recognized over a weighted-average period of 2 years.     Restricted Stock AwardsTime-Based Awards.The fair value of the time-based restricted shares is amortized ratably over the requisite service period, primarily three or four years. The time-based shares vest ratably on each annual anniversary following the grant date that a participant is continuously employed. In January 2012, the Committee awarded a total of 79,889 time-based restricted shares to executive officers that vest ratably over a three-year period ending on January 16, 2015.The following table presents the changes in nonvested time-based awards for the nine months ended 2012:  Shares Weighted-AverageGrant-DateFair Value per Share     Nonvested at December 31, 2011 527,801 $29.29Granted 334,451 26.48Vested (150,264) 30.04Forfeited (16,566) 26.81Nonvested at September 30, 2012 695,422 27.88      As of / Nine Months Ended September 30, 2012 2011 (in thousands, except per share data)    Total intrinsic value of time-based awards vested$4,818 $8,615Total intrinsic value of time-based awards nonvested21,996 10,215Market price per common share as of September 30,31.63 19.39Weighted-average grant date fair value per share26.48 34.14    The total compensation cost related to nonvested time-based awards expected to vest and not yet recognized in our statements of operations as of September 30, 2012 was $13.7 million. This cost is expected to be recognized over a weighted-average period of 2.4 years.  Market-Based Awards.The fair value of the market-based restricted shares is amortized ratably over the requisite service period, primarily three years. Generally, the market-based shares vest if the participant is continuously employed throughout the performance period and the market-based performance measure is achieved, with a maximum vesting period of five years. All compensation cost related to the market-based awards will be recognized if the requisite service period is fulfilled, even if the market condition is not achieved.    In January 2012, the Committee awarded a total of 30,541 market-based restricted shares to our executive officers. In addition to continuous employment, the vesting of these shares is contingent on the Company's total shareholder return ("TSR"), which is essentially the Company’s stock price change including any dividends, as compared to the TSR of a set group of 15 peer companies. The shares are measured over a three-year period ending on December 31, 2014, and can result in a payout between 0% and 200% of the total shares awarded. The weighted-average grant date fair value per market-based share for these awards granted was computed using the Monte Carlo pricing model using the following assumptions:      Nine Months Ended September 30,  2012 2011     Expected term 3 years 3 yearsRisk-free interest rate 0.3% 1.1%Expected volatility 65.3% 74.2%Weighted-average grant date fair value per share $36.54 $58.53The expected term of the awards was based on the requisite service period. The risk-free interest rate was based on the U.S. Treasury yields in effect at the time of grant and extrapolated to approximate the life of the award. The expected volatility was based on our historical volatility. We do not expect to pay or declare dividends in the foreseeable future. The following table presents the change in nonvested market-based awards for the nine months ended 2012: Shares Weighted-AverageGrant-DateFair Value per Share    Nonvested at December 31, 201143,081 $42.05Granted30,541 36.54Nonvested at September 30, 201273,622 41.87    The total compensation cost related to nonvested market-based awards expected to vest and not yet recognized in our statement of operations as of September 30, 2012 was $1 million. This cost is expected to be recognized over a weighted-average period of 2.1 years.   Treasury Share PurchasesIn accordance with our stock-based compensation plans, employees and directors may surrender shares of common stock to pay tax withholding obligations upon the vesting or exercise of stock-based awards. The shares acquired may be retired or reissued to service awards under our 2010 Long-Term Equity Compensation Plan (the "2010 Plan"). For shares that are retired, we first charge any excess of cost over the par value to APIC to the extent we have amounts in APIC, with any remaining excess cost charged to retained earnings. For shares reissued to service awards under the 2010 Plan, shares are recorded at cost and, upon reissuance, we reduce the carrying value of shares acquired and held pursuant to the 2010 Plan by the weighted-average cost per share with an offsetting charge to APIC. During the nine months ended September 30, 2012, we acquired 33,971 shares pursuant to our stock-based compensation plans for payment of tax liabilities, of which 11,796 shares were retired and the remaining 19,930 shares were reissued pursuant to our 2010 Plan. |

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| - Definition
The entire disclosure for compensation-related costs for equity-based compensation, which may include disclosure of policies, compensation plan details, allocation of equity compensation, incentive distributions, equity-based arrangements to obtain goods and services, deferred compensation arrangements, employee stock ownership plan details and employee stock purchase plan details.
+ References
Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Staff Accounting Bulletin (SAB) -Number Topic 14Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 505 -SubTopic 50 -Section 50 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6406099&loc=d3e25284-112666Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5047-113901Reference 5: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Statement of Position (SOP) -Number 93-6 -Paragraph 53 -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.  This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.Reference 6: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 40 -Section 50 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6418621&loc=d3e17540-113929Reference 7: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 123R -Paragraph 64, 65, A240 -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.  This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.Reference 8: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 4 -URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5444-113901
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