Consolidated Statements of Comprehensive Income (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Net income	$ 21,077	$ 21,505	$ 42,470	$ 41,549
Other comprehensive income (loss), before tax:
Change in net unrealized gains (losses) during period	2,816	(35,625)	17,167	(41,342)
Reclassification adjustment for net gains included in income	(17)	12	(88)	4
Defined benefit post-retirement benefits plans:
Change in net actuarial loss	35	35	70	70
Other comprehensive income (loss), before tax	2,834	(35,578)	17,149	(41,268)
Deferred tax benefit (expense) related to other comprehensive income	(1,115)	13,999	(6,748)	16,238
Other comprehensive income (loss), net of tax	1,719	(21,579)	10,401	(25,030)
Comprehensive income, net of tax	$ 22,796	$ (74)	$ 52,871	$ 16,519