Consolidated Statement of Stockholders' Equity (Unaudited) (USD $) In Thousands, unless otherwise specified		Total	Common Stocks [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Income, Net of Tax [Member]
Balance, beginning of year at Dec. 31, 2013		$ 782,833	$ 25	$ 211,574	$ 484,084	$ 87,150
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Shares repurchased			0	(5,567)
Compensation expense and related tax benefit for stock-based award grants				902
Shares issued for stock-based awards			0	1,457
Net income		24,016			24,016
Dividends on common stock ($0.38 per share)					(9,630)
Change in net unrealized investment appreciation	[1]					31,257
Change in liability for underfunded employee benefit plans	[2]					998
All other changes in stockholders’ equity accounts		19,417
Balance, end of year at Jun. 30, 2014		$ 826,266	$ 25	$ 208,366	$ 498,470	$ 119,405

[1] The change in net unrealized appreciation is net of reclassification adjustments and income taxes.

[2] The change in liability for underfunded employee benefit plans is net of reclassification adjustments and income taxes.