Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Operating activities
Net income	$ 70,462	$ 53,666	$ 43,637
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation	1,348	1,298	1,300
Net amortization of investments	16,424	15,243	13,350
Deferred income taxes	1,446	(1,412)	(207)
Net realized (gains) losses on investments	2,494	(697)	1,211
Net realized losses on disposal of assets	664		2
Share-based compensation	1,223	1,519	1,409
Changes in operating assets and liabilities:
Premiums receivable, net	(6,447)	(7,338)	(29,629)
Accrued interest receivable	(48)	(395)	(850)
Deferred policy acquisition costs	(763)	(478)	(752)
Amounts held by others	(27,847)	(1,082)	(5)
Other assets	(1,042)	(4,306)	1,566
Reserves for loss and loss adjustment expenses	30,431	73,045	44,107
Unearned premiums	(593)	4,280	23,768
Reinsurance balances	(5,878)	(10,326)	26,177
Amounts held for others and policyholder deposits	6,621	11,190	238
Accounts payable and other liabilities	4,364	6,477	3,837
Net cash provided by operating activities	92,859	140,684	129,159
Investing activities
Purchases of investments held-to-maturity	(178,010)	(223,028)	(78,144)
Purchases of investments available-for-sale	(135,915)	(149,956)	(135,798)
Purchases of short-term investments	(12,246)	(79,957)	(131,981)
Purchases of other invested assets			(10,000)
Proceeds from maturities of investments held-to-maturity	160,834	112,100	117,770
Proceeds from sales and maturities of investments available-for-sale	78,637	72,535	29,099
Proceeds from sales and maturities of short-term investments	37,833	128,043	112,978
Purchases of property and equipment	(953)	(989)	(1,140)
Net cash (used in)/provided by investing activities	(49,820)	(141,252)	(97,216)
Financing activities
Proceeds from stock option exercises	1,844	2,674	2,344
Tax benefit from share-based payments	2,203	2,841	2,024
Dividends to shareholders	(68,561)	(37,068)	(5,910)
Net cash used in financing activities	(64,514)	(31,553)	(1,542)
Change in cash and cash equivalents	(21,475)	(32,121)	30,401
Cash and cash equivalents at beginning of year	90,956	123,077	92,676
Cash and cash equivalents at end of year	69,481	90,956	123,077
Supplemental disclosure of cash flow information
Income taxes paid	$ 23,851	$ 19,926	$ 12,512