Disclosure of Compensation Related Costs, Share-based Payments [Text Block] | Stock-based Compensation Plans The effect of stock-based compensation on our statements of operations is presented below. 2015 2014 2013 (in millions, except per share data) Decrease in operating income $ 7.0 $ 13.2 $ 11.4 Decrease in net income 4.4 8.1 6.9 Decrease in earnings per basic share 0.03 0.05 0.04 Decrease in earnings per diluted share 0.03 0.05 0.04 We excluded 1,165,414 , 1,103,845 and 1,387,198 instruments from the calculation of diluted earnings per share for 2015 , 2014 and 2013 , respectively, because the effect of including them would have been antidilutive. At September 30, 2015 , there was approximately $3.3 million of unrecognized compensation expense related to stock-based awards not yet vested. We expect to recognize this expense over a weighted average life of approximately 1.1 years. The Mueller Water Products, Inc. 2006 Stock Incentive Plan (“2006 Plan”) authorizes an aggregate of 20,500,000 shares of common stock that may be granted through the issuance of stock-based awards. Any awards canceled are available for reissuance. Generally, all of our employees and members of our board of directors are eligible to participate in the 2006 Plan. At September 30, 2015 , 7,271,214 shares of common stock were available for future grants of awards under the 2006 Plan. This total assumes that the maximum number of shares will be earned for awards for which the final number of shares to be earned has not yet been determined. An award granted under the 2006 Plan vests at such times and in such installments as set by the Compensation and Human Resources Committee of the board of directors, but no award will be exercisable after the ten -year anniversary of the date on which it is granted. Management expects some instruments will be forfeited prior to vesting. Grants to members of our board of the directors are expected to vest fully. Based on historical forfeitures, we expect grants to others to be forfeited at an annual rate of 3% . Restricted Stock Units. Depending on the specific terms of each award, restricted stock units generally vest on the three -year anniversary of the grant date, or ratably over the life of the award, usually three years, on each anniversary date of the original grant. Restricted stock units granted since November 2007 also vest upon the Retirement (as defined in the 2006 Plan) of a participant. Compensation expense for restricted stock units is recognized between the grant date and the vesting date (or the date on which a participant becomes Retirement-eligible, if sooner) on a straight-line basis for each tranche of each award. Fair values of restricted stock units are determined using the closing price of our common stock on the respective dates of grant. Restricted stock unit activity under the 2006 Plan is summarized below. Restricted stock units Weighted average grant date fair value per unit Weighted average remaining contractual term (years) Aggregate intrinsic value (millions) Outstanding at September 30, 2012 2,423,762 $ 4.13 1.0 Granted 509,338 5.37 Vested (995,037 ) 4.77 $ 5.6 Cancelled (12,723 ) 12.28 Outstanding at September 30, 2013 1,925,340 4.30 0.9 Granted 381,012 8.51 Vested (1,099,591 ) 4.94 9.4 Cancelled — — Outstanding at September 30, 2014 1,206,761 5.04 0.7 Granted 459,659 9.70 Vested (793,630 ) 3.99 7.7 Cancelled — — Outstanding at September 30, 2015 872,790 $ 8.45 0.8 Performance Shares. Performance-based restricted stock units (“PRSUs”) represent a target number of units that may be paid out at the end of a multi-year award cycle consisting of annual performance periods coinciding with our fiscal years. As determined at the date of grant, PRSUs may settle in cash-value equivalent of, or directly in, shares of our common stock. Settlement will range from zero to two times the number of PRSUs granted, depending on our financial performance against predetermined targets. Performance goals are established within 90 days of the beginning of each performance period by the Compensation and Human Resources Committee of our board of directors (“Committee”). At the end of each annual performance period, the Committee confirms performance against the applicable performance targets. PRSUs do not convey voting rights or earn dividends. PRSUs vest on the last day of an award cycle, unless vested sooner due to a “Change of Control” of the Company, or the death, disability or Retirement of a participant. The 243,992 cash-settled PRSUs granted in the quarter ended December 31, 2012 settled in the quarter ended December 31, 2014 for $4.0 million . Compensation expense for cash-settled PRSU’s has been recognized over the applicable performance periods based on the estimated performance factor and the closing price of our common stock at each balance sheet date. The stock-settled PRSUs granted in 2013, 2014 and 2015 will be settled in November 2015 , December 2016 and December 2017 , respectively. Compensation expense for stock-settled PRSU’s is recognized over the applicable performance periods based on the estimated performance factors and the closing price of our common stock on the date each performance goal is established. The stock prices used to value the awards were $5.22 for the 2013 performance period, $8.52 for the 2014 performance period and $9.78 for the 2015 performance period. Stock-settled PRSUs activity under the 2006 Plan is summarized below. Award date Performance period Units awarded Shares earned November 27, 2012 2013 135,553 271,106 2014 135,553 271,106 2015 135,552 0 December 3, 2013 2014 90,841 181,682 2015 90,841 0 2016 90,849 n/a December 2, 2014 2015 80,233 0 2016 80,229 n/a 2017 80,229 n/a Stock Options. Outstanding stock options generally vest on each anniversary date of the original grant ratably over three years. Stock options granted since November 2007 also vest upon the Retirement of a participant. Compensation expense for stock options is recognized between the grant date and the vesting date (or the date on which a participant becomes Retirement-eligible, if sooner) on a straight-line basis for each tranche of each award. Stock option activity under the 2006 Plan is summarized below. Options Weighted average exercise price per option Weighted average remaining contractual term (years) Aggregate intrinsic value (millions) Outstanding at September 30, 2012 5,522,610 $ 6.30 6.8 $ 3.5 Granted 125,780 5.91 Exercised (384,475 ) 4.97 1.2 Cancelled (139,209 ) 12.52 Outstanding at September 30, 2013 5,124,706 6.22 5.9 14.6 Granted 86,904 8.58 Exercised (587,964 ) 4.61 — Cancelled (71,411 ) 12.92 Outstanding at September 30, 2014 4,552,235 6.37 5.0 13.6 Granted 97,119 9.97 Exercised (506,632 ) 3.42 3.2 Cancelled (150,056 ) 13.90 Outstanding at September 30, 2015 3,992,666 $ 6.54 4.2 $ 9.3 Exercisable at September 30, 2015 3,799,877 $ 6.43 3.9 $ 9.3 Expected to vest after September 30, 2015 192,789 $ 8.76 8.6 $ 0.1 Stock option exercise prices are equal to the closing price of our common stock on the relevant grant date. The ranges of exercise prices for stock options outstanding at September 30, 2015 are summarized below. Exercise price Options Weighted average exercise price Weighted average remaining contractual term (years) Exercisable options Weighted average exercise price $ 0.00 - $ 4.99 1,395,711 $ 3.34 5.4 1,395,711 $ 3.34 $ 5.00 - $ 9.99 1,799,892 6.07 4.3 1,607,103 5.74 $ 10.00 - $ 14.99 515,846 11.30 2.0 515,846 11.30 $ 15.00 - $ 20.99 281,217 16.76 0.8 281,217 16.76 3,992,666 $ 6.54 4.2 3,799,877 $ 6.43 Compensation expense attributed to stock options is based on the fair value of the awards on their respective grant dates, as determined using a Black-Scholes model. The weighted average grant-date fair values of stock options granted and the weighted average assumptions used to determine these fair values are indicated below. 2015 2014 2013 Grant-date fair value $ 5.93 $ 5.13 $ 5.91 Risk-free interest rate 1.74 % 2.44 % 1.63 % Dividend yield 0.80 % 1.10 % 2.17 % Expected life (years) 8.0 8.0 8.0 Expected annual volatility 0.6199 0.6386 0.6696 The risk-free interest rate is based on the U.S. Treasury zero-coupon yield in effect at the grant date with a term equal to the expected life. The expected dividend yield is based on our estimated annual dividend and stock price history at the grant date. The expected term represents the period of time the awards are expected to be outstanding. Employee Stock Purchase Plan. The Mueller Water Products, Inc. 2006 Employee Stock Purchase Plan (“ESPP”) authorizes the sale of up to 4,000,000 shares of our common stock to employees. Generally, all full-time, active employees are eligible to participate in the ESPP, subject to certain restrictions. Employee purchases are funded through payroll deductions, and any excess payroll withholdings are returned to the employee. The price for shares purchased under the ESPP is the lower of 85% of closing price on the first day or the last day of the offering period. At September 30, 2015 , 1,470,253 shares were available for issuance under the ESPP. Phantom Plan. In 2012, the Company adopted the Mueller Water Products, Inc. Phantom Plan (“Phantom Plan”). The Phantom Plan awards were awarded to certain non-officer employees. Outstanding phantom awards vest ratably on each anniversary date of the original grant for three years. Compensation expense for Phantom Plan awards is charged against income on a straight-line basis for each tranche of each award based on the closing price of our common stock at each balance sheet date. Phantom Plan awards are payable in cash and recorded as liability awards. The outstanding Phantom Plan awards had a fair value of $7.66 per award at September 30, 2015 and our liability for such awards was $2.7 million . Phantom Plan activity for 2015 is summarized below. Phantom Plan units Weighted average grant date fair value per unit Weighted average remaining contractual term (years) Aggregate intrinsic value (millions) Outstanding at September 30, 2012 358,866 $ 2.03 1.2 Granted 382,605 5.22 Vested (119,637 ) $ 0.7 Cancelled (12,852 ) 2.03 Outstanding at September 30, 2013 608,982 4.03 1.0 Granted 304,815 8.52 Vested (240,739 ) 2.1 Cancelled (29,770 ) 5.29 Outstanding at September 30, 2014 643,288 6.22 0.8 Granted 289,524 9.78 Vested (317,409 ) 3.1 Cancelled (56,525 ) 8.29 Outstanding at September 30, 2015 558,878 $ 8.49 0.8 |