CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015		Jun. 30, 2014
Statement of Comprehensive Income [Abstract]
Net income	$ 10,333	$ 6,982	$ 21,558		$ 17,910
Investments available-for-sale:
Net change in unrealized gains (losses) on investments available-for-sale	(4,819)	6,361	(185)		13,493
Related income tax (expense) benefit	1,915	(2,522)	74		(5,345)
Net investment gains reclassified into earnings	19	0	19		0
Related income tax expense	(8)	0	(8)		0
Net effect on other comprehensive income (loss)	(2,893)	3,839	(100)		8,148
Defined benefit pension plan:
Recognition of unrealized gain (loss)	259	68	551	[1]	116	[1]
Related income tax (expense) benefit	(104)	(24)	(220)		(61)
Net effect on other comprehensive income (loss)	155	44	331		55
Total other comprehensive income (loss)	(2,738)	3,883	231		8,203
Comprehensive income	$ 7,595	$ 10,865	$ 21,789		$ 26,113

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