Consolidated Statements of Comprehensive Income (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Net income	$ 16,155	$ 11,921	$ 41,379	$ 31,281
Other comprehensive income (loss), before tax:
Change in net unrealized gains (losses) during period	931	2,781	(175)	24,200
Reclassification adjustment for net gains included in income	(66)	(38)	(295)	(56)
Defined benefit post-retirement benefits plans:
Change in net actuarial loss	35	35	102	104
Other comprehensive income (loss), before tax	900	2,778	(368)	24,248
Deferred tax benefit (expense) related to other comprehensive income	(354)	(1,093)	145	(9,541)
Other comprehensive income (loss), net of tax	546	1,685	(223)	14,707
Comprehensive income, net of tax	$ 16,701	$ 13,606	$ 41,156	$ 45,988