Consolidated Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019
Operating Activities
Net income	$ 119,294	$ 189,764
Adjustments to reconcile net income to net cash provided by (used in) operating activities:
Depreciation and amortization	44,435	42,346
Stock-based compensation expense	13,935	15,857
Undistributed gains of equity method investments	(5,146)	(8,832)
Distributions in excess of current year income of equity method investments	3,136	2,267
Net realized and unrealized losses (gains)	24,296	(15,295)
Loss (gain) on disposal of fixed assets	17	(21)
Changes in assets and liabilities:
Increase in reserve for loss and loss expense, net of reinsurance recoverable	190,796	134,951
Increase in unearned premiums, net of prepaid reinsurance	114,672	122,460
(Increase) decrease in net federal income taxes	(10,775)	2,408
Increase in premiums receivable	(28,239)	(89,962)
Increase in deferred policy acquisition costs	(21,523)	(26,627)
Increase in interest and dividends due or accrued	(1,507)	(1,460)
Decrease in accrued salaries and benefits	(33,677)	(16,261)
Increase in other assets	(23,388)	(35,810)
(Decrease) increase in other liabilities	(5,443)	414
Net Cash Provided by Operating Activities	380,883	316,199
Investing Activities
Purchase of fixed income securities, available-for-sale	(1,373,226)	(1,330,827)
Purchase of commercial mortgage loans	(29,800)	0
Purchase of equity securities	(87,307)	(40,233)
Purchase of other investments	(61,051)	(41,248)
Purchase of short-term investments	(4,475,128)	(4,108,414)
Sale of fixed income securities, available-for-sale	411,263	461,825
Proceeds from commercial mortgage loans	109	0
Sale of short-term investments	4,377,024	4,106,643
Redemption and maturities of fixed income securities, held-to-maturity	1,646	10,062
Redemption and maturities of fixed income securities, available-for-sale	738,238	413,220
Sale of equity securities	1,320	125,302
Sale of other investments	3,879	18,016
Distributions from other investments	12,890	19,054
Purchase of property and equipment	(17,858)	(24,424)
Fixed asset disposals	0	35
Net Cash Used in Investing Activities	(498,001)	(390,989)
Financing Activities
Dividends to stockholders	(39,972)	(34,440)
Acquisition of treasury stock	(7,039)	(8,071)
Net proceeds from stock purchase and compensation plans	5,478	5,599
Proceeds from borrowings	487,000	355,757
Repayments of borrowings	(320,000)	(250,000)
Repayments of finance lease obligations	(429)	(811)
Net Cash Provided by Financing Activities	125,038	68,034
Cash and restricted cash, beginning of year	7,975	16,919
Cash and restricted cash, end of period	15,895	10,163
Net increase (decrease) in cash and restricted cash	$ 7,920	$ (6,756)