| Schedule of Quarterly Financial Information [Table Text Block] |
|
Ìý
|
Ìý
|
Quarter ended
|
Ìý
|
|
Ìý
|
Ìý
|
December 31,
2013
|
Ìý
|
Ìý
|
September 30,
2013
|
Ìý
|
Ìý
|
June 30,
2013
|
Ìý
|
Ìý
|
March 31,
2013
|
Ìý
|
|
Income
|
Ìý
|
$
|
12,503,683
|
Ìý
|
Ìý
|
$
|
14,936,609
|
Ìý
|
Ìý
|
$
|
9,953,933
|
Ìý
|
Ìý
|
$
|
6,726,854
|
Ìý
|
|
Income before income taxes
|
Ìý
|
$
|
11,145,275
|
Ìý
|
Ìý
|
$
|
14,103,915
|
Ìý
|
Ìý
|
$
|
9,049,678
|
Ìý
|
Ìý
|
$
|
5,843,710
|
Ìý
|
|
Net income
|
Ìý
|
$
|
7,519,106
|
Ìý
|
Ìý
|
$
|
9,431,118
|
Ìý
|
Ìý
|
$
|
6,130,440
|
Ìý
|
Ìý
|
$
|
4,137,844
|
Ìý
|
|
Net income per Sub-share Certificate
|
Ìý
|
$
|
0.88
|
Ìý
|
Ìý
|
$
|
1.10
|
Ìý
|
Ìý
|
$
|
0.71
|
Ìý
|
Ìý
|
$
|
0.47
|
Ìý
|
|
Ìý
|
Ìý
|
Quarter ended
|
Ìý
|
|
Ìý
|
Ìý
|
December 31,
2012
|
Ìý
|
Ìý
|
September 30,
2012
|
Ìý
|
Ìý
|
June 30,
2012
|
Ìý
|
Ìý
|
March 31,
2012
|
Ìý
|
|
Income
|
Ìý
|
$
|
7,276,793
|
Ìý
|
Ìý
|
$
|
7,043,281
|
Ìý
|
Ìý
|
$
|
8,706,738
|
Ìý
|
Ìý
|
$
|
9,580,079
|
Ìý
|
|
Income before income taxes
|
Ìý
|
$
|
6,218,508
|
Ìý
|
Ìý
|
$
|
6,369,983
|
Ìý
|
Ìý
|
$
|
7,956,109
|
Ìý
|
Ìý
|
$
|
8,778,286
|
Ìý
|
|
Net income
|
Ìý
|
$
|
4,113,797
|
Ìý
|
Ìý
|
$
|
4,311,092
|
Ìý
|
Ìý
|
$
|
5,284,674
|
Ìý
|
Ìý
|
$
|
5,938,255
|
Ìý
|
|
Net income per Sub-share Certificate
|
Ìý
|
$
|
0.47
|
Ìý
|
Ìý
|
$
|
0.48
|
Ìý
|
Ìý
|
$
|
0.59
|
Ìý
|
Ìý
|
$
|
0.65
|
Ìý
|
|