Income Taxes (Tables)

12 Months Ended

Dec. 31, 2023

Income Tax Disclosure [Abstract]

Schedule of Deferred Tax Assets and Deferred Tax Liabilities

(in thousands)	2023		2022
Deferred tax assets:
Tax discounting of unpaid losses and settlement expenses	$	25,491	$	23,788
Unearned premium offset		32,763		27,158
Net unrealized depreciation of securities		—		19,839
Deferred compensation		4,170		4,058
Share-based compensation expense		3,556		3,202
Capitalized research and development costs		4,970		2,544
Lease liability		3,113		3,026
Other		2,949		938
Deferred tax assets before allowance	$	77,012	$	84,553
Less valuation allowance		—		—
Total deferred tax assets	$	77,012	$	84,553
Deferred tax liabilities:
Net unrealized appreciation of securities	$	10,981	$	—
Deferred policy acquisition costs		30,779		26,850
Lease asset		2,870		2,681
Discounting of unpaid losses and settlement expenses - Tax Cuts and Jobs Act (TCJA) implementation offset		1,272		1,909
Fixed assets		2,745		3,083
Intangible assets		1,552		1,543
Undistributed earnings of unconsolidated investees		10,351		7,399
Other		590		819
Total deferred tax liabilities	$	61,140	$	44,284
Net deferred tax asset	$	15,872	$	40,269

Schedule of Reconciliation of Income Tax Expense Attributable to Income from Operations with Amounts Computed by Applying U.S. Federal Tax Rate to Pretax Income from Continuing Operations

(in thousands)	2023					2022					2021
Provision for income taxes at the statutory federal tax rates	$	79,226		21.0	%	$	151,342		21.0	%	$	72,307		21.0	%
Increase (reduction) in taxes resulting from:
Excess tax benefit on share-based compensation		(3,774)		(1.0)	%		(4,491)		(0.6)	%		(3,090)		(0.9)	%
Tax-exempt interest income		(1,092)		(0.3)	%		(1,143)		(0.2)	%		(1,219)		(0.3)	%
Dividends received deduction		(938)		(0.2)	%		(912)		(0.1)	%		(891)		(0.3)	%
Tax credit		(3,644)		(1.0)	%		(6,204)		(0.9)	%		(4,657)		(1.3)	%
ESOP dividends paid deduction		(1,591)		(0.4)	%		(4,171)		(0.6)	%		(1,566)		(0.5)	%
Nondeductible expenses		3,351		0.9	%		1,263		0.2	%		3,834		1.1	%
Other items, net		1,116		0.3	%		1,583		0.2	%		249		0.1	%
Total	$	72,654	​	19.3	%	$	137,267	​	19.0	%	$	64,967	​	18.9	%