Condensed Consolidated Balance Sheets (Parenthetical) - USD ($)	Jun. 30, 2020	Dec. 31, 2019
Debt securities, available-for-sale	$ 4,581,531,000	$ 4,476,358,000
Short-term investments	216,484,000	67,353,000
Cash and cash equivalents	297,282,000	135,942,000
Other investments	287,735,000	311,287,000
Restricted cash and cash equivalents	37,726,000	28,521,000
Accrued investment income	29,499,000	30,927,000
Premiums and other receivables, net	1,487,734,000	1,428,948,000
Deferred acquisition costs	275,931,000	263,523,000
Reinsurance recoverable, net	1,292,636,000	1,394,308,000
Prepaid reinsurance premiums	518,082,000	575,747,000
Premises and equipment, net	388,889,000	403,827,000
Intangible assets, net	350,821,000	365,823,000
Prepaid and other assets	74,165,000	94,642,000
Unpaid loss and loss adjustment expense reserves	2,826,584,000	2,886,414,000
Unearned premiums and other revenue	2,328,447,000	2,312,241,000
Reinsurance payable	461,896,000	562,844,000
Accounts payable and accrued expenses	327,929,000	315,366,000
Other liabilities	411,045,000	376,169,000
Preferred stock	$ 450,000,000	$ 450,000,000
Preferred stock, par value (in dollars per share)	$ 0.01
Preferred stock, shares authorized (in shares)	10,000,000
Preferred Stock, Shares Issued (in shares)	2,565,120	2,565,120
Preferred stock, shares outstanding (in shares)	2,565,120	2,565,120
Aggregate liquidation preference	$ 450,000,000	$ 450,000,000
Common stock, par value (in dollars per share)	$ 0.01
Common Stock, Shares Authorized	150,000,000
Common Stock, Issued (in shares)	113,856,628	113,368,811
Common Stock, Outstanding (in shares)	113,397,545	113,368,811
Treasury Stock, Common, Shares	459,083	0
Debt securities, available-for sale, allowance for expected credit losses	$ 1,203,000	$ 0
Premiums and other receivables, allowance for expected credit losses	40,078,000	24,067,000
Reinsurance recoverable, allowance for expected credit losses	517,000	0
Reciprocal Exchanges
Debt securities, available-for-sale	320,773,000	324,249,000
Short-term investments	19,330,000	5,245,000
Cash and cash equivalents	4,000	959,000
Restricted cash and cash equivalents	233,000	24,000
Accrued investment income	1,939,000	2,001,000
Premiums and other receivables, net	49,649,000	55,859,000
Deferred acquisition costs	23,097,000	23,307,000
Reinsurance recoverable, net	113,321,000	119,125,000
Prepaid reinsurance premiums	82,684,000	105,894,000
Premises and equipment, net	18,000	241,000
Intangible assets, net	3,135,000	3,225,000
Prepaid and other assets	4,310,000	3,521,000
Unpaid loss and loss adjustment expense reserves	200,270,000	205,786,000
Unearned premiums and other revenue	226,403,000	252,553,000
Reinsurance payable	23,907,000	35,689,000
Accounts payable and accrued expenses	7,753,000	8,497,000
Other liabilities	30,279,000	30,803,000
Debt securities, available-for sale, allowance for expected credit losses	149,000
Premiums and other receivables, allowance for expected credit losses	1,867,000	541,000
Reinsurance recoverable, allowance for expected credit losses	173,000
Related Parties
Other investments	235,458,000	238,841,000
Accrued investment income	$ 2,405,000	$ 2,391,000