Condensed Consolidated Statements of Cash Flows (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
Cash flows from operating activities:
Net income	$ 24.7	$ 27.1
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization, net	5.5	3.4
Share-based compensation	1.0	1.0
Net realized gains on investments	(3.8)	(10.7)
Changes in operating assets and liabilities:
Deferred policy acquisition costs	(0.9)	(2.9)
Accrued investment income and other assets	(2.0)	(1.5)
Postretirement and pension benefits	(0.7)	1.7
Other liabilities and due to/from affiliates, net	(49.6)	(10.6)
Reinsurance recoverable on losses and loss expenses payable and prepaid reinsurance premiums	1.6	(0.6)
Losses and loss expenses payable	14.5	(8.2)
Unearned premiums	(8.2)	2.9
Federal income taxes	9.0	0.7
Cash provided from December 31, 2014 unearned premium transfer related to the homeowners quota share arrangement	63.5	0
Net cash provided by operating activities	54.6	2.3
Cash flows from investing activities:
Purchases of fixed maturities available-for-sale	(212.8)	(137.2)
Purchases of equity securities available-for-sale	(19.7)	(38.0)
Purchases of other invested assets	(3.9)	(0.4)
Maturities, calls and pay downs of fixed maturities available-for-sale	83.2	68.9
Sales of fixed maturities available-for-sale	62.5	71.3
Sales of equity securities available-for-sale	21.5	34.6
Sales of other invested assets available-for-sale	0.2	0.2
Net cash used in investing activities	(69.0)	(0.6)
Cash flows from financing activities:
Proceeds from issuance of common stock	0.7	0.6
Payments to acquire treasury stock	(0.1)	(0.1)
Payment of dividends	(4.1)	(4.2)
Net cash used in financing activities	(3.5)	(3.7)
Net decrease in cash and cash equivalents	(17.9)	(2.0)
Cash and cash equivalents at beginning of period	86.3	80.3
Cash and cash equivalents at end of period	68.4	78.3
Supplemental disclosures:
Interest paid (affiliates $0.2 and $0.2, respectively)	$ 1.3	$ 1.3