Basic and diluted earnings per common share were calculated as follows (in thousands, except per share amounts):
Three Months Ended June 30,
Six Months Ended June 30,
2018
2017
2018
2017
Basic weighted average number of shares outstanding
40,647
40,317
40,568
40,248
Effect of dilutive securities:
Convertible debt (1)
—
1,991
—
2,083
Unvested restricted stock
517
473
625
505
Diluted average shares outstanding
41,164
42,781
41,193
42,836
Net earnings as reported
$
53,838
$
41,580
$
97,712
$
65,152
Interest attributable to Convertible Notes, net of income taxes (1)
—
354
—
739
Net earnings for diluted earnings per share
$
53,838
$
41,934
$
97,712
$
65,891
Basic earnings per share
$
1.32
$
1.03
$
2.41
$
1.62
Diluted earnings per share (1)
$
1.31
$
0.98
$
2.37
$
1.54
Antidilutive stock not included in the calculation of diluted earnings per share
1
59
1
2
(1)
In accordance with ASC 260-10, Earnings Per Share, ("ASC 260-10") we calculate the dilutive effect of convertible securities using the "if-converted" method based on the number of days our Convertible Notes were outstanding during the period. All of the Convertible Notes were retired in the second half of 2017.