CONSOLIDATED STATEMENTS OF CHANGES IN SHAREHOLDERS' EQUITY - USD ($) $ in Thousands	Total		Common stock	Additional paid-in capital	Retained earnings	Accumulated other comprehensive income (loss), net of taxes	Treasury stock, at cost
Beginning balance at Dec. 31, 2012			$ 62	$ 383,135	$ 921,969	$ 367,089	$ (426,452)
Options exercised, 2015, 85,532 shares; 2014, 435,665 shares; 2013, 1,158,537 shares			2
Conversion of common stock units, 2015, 8,293 shares; 2014, 10,834 shares; 2013, 11,851 shares			0
Conversion of restricted stock units, 2015, 198,681 shares; 2014, 169,444 shares; 2013, 146,930 shares			0
Options exercised and conversion of common stock units and restricted stock units				22,502
Share-based compensation expense				1,419
Net income	$ 110,893				110,893
Cash dividends, 2015, $1.00 per share; 2014, $0.92 per share; 2013, $0.78 per share					(32,550)
Change in net unrealized gains on fixed maturities and equity securities	(248,410)	[1],[2]				(248,410)
Change in net funded status of pension and other postretirement benefit obligations	3,535	[1]				3,535
Acquisition of shares, 2015, 663,092 shares; 2014, 190,876 shares; 2013, 173,629 shares							(3,889)
Ending balance at Dec. 31, 2013	1,099,305		64	407,056	1,000,312	122,214	(430,341)
Options exercised, 2015, 85,532 shares; 2014, 435,665 shares; 2013, 1,158,537 shares			0
Conversion of common stock units, 2015, 8,293 shares; 2014, 10,834 shares; 2013, 11,851 shares			0
Conversion of restricted stock units, 2015, 198,681 shares; 2014, 169,444 shares; 2013, 146,930 shares			0
Options exercised and conversion of common stock units and restricted stock units				13,906
Share-based compensation expense				1,270
Net income	104,243				104,243
Cash dividends, 2015, $1.00 per share; 2014, $0.92 per share; 2013, $0.78 per share					(39,237)
Change in net unrealized gains on fixed maturities and equity securities	163,564	[1],[2]				163,564
Change in net funded status of pension and other postretirement benefit obligations	(1,177)	[1]				(1,177)
Acquisition of shares, 2015, 663,092 shares; 2014, 190,876 shares; 2013, 173,629 shares							(5,411)
Ending balance at Dec. 31, 2014	1,336,463		64	422,232	1,065,318	284,601	(435,752)
Options exercised, 2015, 85,532 shares; 2014, 435,665 shares; 2013, 1,158,537 shares			0
Conversion of common stock units, 2015, 8,293 shares; 2014, 10,834 shares; 2013, 11,851 shares			0
Conversion of restricted stock units, 2015, 198,681 shares; 2014, 169,444 shares; 2013, 146,930 shares			1
Options exercised and conversion of common stock units and restricted stock units				13,605
Share-based compensation expense				6,811
Net income	93,482				93,482
Cash dividends, 2015, $1.00 per share; 2014, $0.92 per share; 2013, $0.78 per share					(42,523)
Change in net unrealized gains on fixed maturities and equity securities	(122,387)	[1],[2]				(122,387)
Change in net funded status of pension and other postretirement benefit obligations	1,159	[1]				1,159
Acquisition of shares, 2015, 663,092 shares; 2014, 190,876 shares; 2013, 173,629 shares							(21,950)
Ending balance at Dec. 31, 2015	$ 1,264,661		$ 65	$ 442,648	$ 1,116,277	$ 163,373	$ (457,702)

[1] All amounts are net of tax.

[2] The pretax amounts reclassified from accumulated other comprehensive income, $11,667, $10,943 and $22,245, are included in net realized investment gains and losses and the related tax expenses, $4,083, $3,830 and $7,786, are included in income tax expense in the Consolidated Statements of Operations for the years ended December 31, 2015, 2014 and 2013, respectively.