EXHIBIT 12

COMPUTATION OF RATIOS

(UNAUDITED)

Our consolidated ratios of earnings to fixed charges for each of the fiscal years ended December 31, 2017, 2016, 2015, 2014 and 2013 are as follows:

Year Ended December 31, | ||||||||||||||||||||||

2017 | 2016 | 2015 | 2014 | 2013 | ||||||||||||||||||

Earnings: | ||||||||||||||||||||||

Pretax income from continuing operations | $ | 80,512 | $ | 86,525 | $ | 76,915 | $ | 67,055 | $ | 54,503 | ||||||||||||

Fixed charges | 31,723 | 22,490 | 25,974 | 32,920 | 44,789 | |||||||||||||||||

Capitalized interest | — | — | (1,486 | ) | (603 | ) | — | |||||||||||||||

Total earnings - Numerator | $ | 112,235 | $ | 109,015 | $ | 101,403 | $ | 99,372 | $ | 99,292 | ||||||||||||

Fixed charges: | ||||||||||||||||||||||

Interest and debt expense | $ | 31,474 | $ | 22,241 | $ | 24,239 | $ | 32,068 | $ | 44,540 | ||||||||||||

1/3 of rent expense - interest factor | 249 | 249 | 249 | 249 | 249 | |||||||||||||||||

Capitalized interest | — | — | 1,486 | 603 | — | |||||||||||||||||

Total fixed charges - Denominator | $ | 31,723 | $ | 22,490 | $ | 25,974 | $ | 32,920 | $ | 44,789 | ||||||||||||

Ratio of earnings to fixed charges | 3.54 | 4.85 | 3.90 | 3.02 | 2.22 |

Earnings equals (i) income from continuing operations before income taxes, plus (ii) fixed charges, minus (iii) capitalized interest. Fixed charges equals (i) interest and debt expense, plus (ii) the portion of operating lease rental expense that is representative of the interest factor, which is one-third of operating lease rentals and (iii) capitalized interest.