Statements of Cash Flow (Tables)

12 Months Ended

Dec. 31, 2017

Supplemental Cash Flow Information [Abstract]

Schedule of Cash Flow, Supplemental Disclosures

($ in thousands)	2017		2016	2015
Cash paid during the period for:
Interest	$	23,905	22,098	21,892
Federal income tax	62,000		46,405	39,500
Non-cash items:
Exchange of fixed income securities, AFS	22,511		23,579	36,792
Exchange of fixed income securities, HTM	—		—	15,257
Corporate actions related to equity securities, AFS1	4,725		3,263	4,239
Assets acquired under capital lease arrangements	278		3,151	6,760
Non-cash purchase of property and equipment	—		78	—