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]
Compensation expense and related tax benefit for stock-based award grants				507
Shares issued for stock-based awards			0	823
Net income		13,331			13,331
Dividends on common stock ($0.18 per share)					(4,567)
Change in net unrealized investment appreciation	[1]					14,681
Change in liability for underfunded employee benefit plans	[2]					499
All other changes in stockholders’ equity accounts		11,943
Balance, end of year at Mar. 31, 2014		$ 808,107	$ 25	$ 212,904	$ 492,848	$ 102,330

[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.