Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017
Operating activities
Net income	$ 52,826	$ 45,582
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation	748	760
Net amortization of investments	8,414	10,815
Deferred income taxes	1,388	342
Net realized losses on investments	1,471	761
Net unrealized gains on equity securities	(259)
Net realized losses on disposal of assets		2
Share-based compensation	1,074	1,283
Changes in operating assets and liabilities:
Premiums receivable, net	(4,391)	(2,492)
Accrued interest receivable	(141)	125
Deferred policy acquisition costs	(1,075)	(1,606)
Amounts held by others	(7,855)	27,848
Other assets	2,692	(5,131)
Reserves for loss and loss adjustment expenses	19,284	12,250
Unearned premiums	7,897	3,792
Reinsurance balances	(19,136)	(1,320)
Amounts held for others and policyholder deposits	2,621	2,503
Accounts payable and other liabilities	5,185	6,813
Net cash provided by operating activities	70,743	102,327
Investing activities
Purchases of investments held-to-maturity	(71,872)	(149,981)
Purchases of investments available-for-sale	(82,519)	(79,116)
Purchases of equity securities	(5,251)	(7,499)
Purchases of short-term investments	(133,355)	(53,789)
Proceeds from maturities of investments held-to-maturity	85,322	112,715
Proceeds from sales and maturities of investments available-for-sale	79,539	82,270
Proceeds from sales and maturities of short-term investments	48,965	17,610
Proceeds from redemptions of other investments	130	9,000
Purchases of property and equipment	(1,083)	(446)
Net cash used in investing activities	(80,124)	(69,236)
Financing activities
Proceeds from stock option exercises	67
Dividends to shareholders	(12,921)	(11,649)
Net cash used in financing activities	(12,854)	(11,649)
Change in cash and cash equivalents	(22,235)	21,442
Cash and cash equivalents at beginning of period	55,559	58,936
Cash and cash equivalents at end of period	$ 33,324	$ 80,378