CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013		Dec. 31, 2012		Dec. 31, 2011
Net income	$ 44,422		$ 36,554		$ 34,102
Investments available-for-sale:
Net change in unrealized gains (losses) on investments available-for-sale	(33,214)		(40)		26,722
Related income tax (expense) benefit	13,245		16		(10,656)
Net investment gains reclassified into earnings	115		459		292
Related income tax expense	(46)		(183)		(116)
Net effect on other comprehensive income (loss) for the period	(19,900)		252		16,242
Defined benefit pension plan:
Recognition of unrealized gain (loss)	9,340	[1]	(3,639)	[1]	(622)	[1]
Related income tax (expense) benefit	(3,722)		1,451		248
Net effect on other comprehensive income (loss) for the period	5,618		(2,188)		(374)
Total other comprehensive income	(14,282)		(1,936)		15,868
Comprehensive income	$ 30,140		$ 34,618		$ 49,970

[1] This amount is included in the computation of net periodic benefit cost, see Note 14