Accumulated Other Comprehensive Income (Tables)
 3 Months Ended
Mar. 31, 2018
Stockholders' Equity Note [Abstract]  
Schedule of Other Comprehensive Income Before and After Tax
The components of other comprehensive income before and after tax are as follows ($ in thousands):
 
Three months ended March 31,
 
2018
 
2017
 
Before Tax
 
Income Tax
 
Net
 
Before Tax
 
Income Tax
 
Net
Accumulated change in post-retirement benefit liability, beginning of period
$
829

 
$
(290
)
 
$
539

 
$
1,033

 
$
(361
)
 
$
671

Cumulative effect of change in accounting principle
0

 
116

 
116

 
0

 
0

 
0

Effect on other comprehensive income
(2
)
 
0

 
(1
)
 
(13
)
 
4

 
(8
)
Accumulated change in post-retirement benefit liability, end of period
827

 
(174
)
 
653

 
1,020

 
(357
)
 
663

Accumulated unrealized gains on investments, net, beginning of period
28,421

 
(9,204
)
 
19,217

 
11,133

 
(3,896
)
 
7,236

Cumulative effect of change in accounting principle
(27,192
)
 
8,948

 
(18,244
)
 
0

 
0

 
0

Other comprehensive (loss) income before reclassification (1)
(18,344
)
 
3,852

 
(14,492
)
 
10,664

 
(3,733
)
 
6,932

Reclassification adjustment for other-than-temporary impairments included in net income (1)
1,588

 
(334
)
 
1,255

 
10

 
(3
)
 
6

Reclassification adjustment for realized losses (gains) included in net income (1)
518

 
(109
)
 
409

 
(519
)
 
182

 
(337
)
Effect on other comprehensive income
(16,238
)
 
3,410

 
(12,828
)
 
10,155

 
(3,554
)
 
6,601

Accumulated unrealized (losses) gains on investments, net, end of period
(15,009
)
 
3,154

 
(11,855
)
 
21,288

 
(7,451
)
 
13,837

Accumulated other comprehensive income, beginning of period
29,250

 
(9,494
)
 
19,756

 
12,165

 
(4,258
)
 
7,907

Cumulative effect of change in accounting principle
(27,192
)
 
9,064

 
(18,128
)
 
0

 
0

 
0

Change in post-retirement benefit liability
(2
)
 
0

 
(1
)
 
(13
)
 
4

 
(8
)
Change in unrealized (losses) gains on investments, net (1)
(16,238
)
 
3,410

 
(12,828
)
 
10,155

 
(3,554
)
 
6,601

Effect on other comprehensive income
(43,432
)
 
12,474

 
(30,958
)
 
10,143

 
(3,550
)
 
6,593

Accumulated other comprehensive (loss) income, end of period
$
(14,182
)
 
$
2,980

 
$
(11,202
)
 
$
22,308

 
$
(7,808
)
 
$
14,500


(1) The amounts for 2018 are for fixed maturities only.