CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Net Income	$ 44,453	$ 41,482	$ 41,954
Other comprehensive income (loss), before tax expense (benefit):
Unrealized holding gains (losses) on securities arising during the period	25,153	(34,975)	(661)
Less: reclassification adjustment for (gains) losses on securities included in net income	(550)	1,158	(192)
Unrealized holding gains on derivatives arising during the period	472	0	0
Reclassification adjustment for gains on derivatives included in net income	(10)	0	0
Unrealized (losses) gains for postretirement obligations:
Transition obligation	0	0	2
Net (loss) gain	(313)	219	(300)
Total other comprehensive income (loss), before tax expense (benefit)	24,752	(33,598)	(1,151)
Income tax expense (benefit) related to items of other comprehensive income (loss)	8,663	(11,751)	(409)
Comprehensive Income	$ 60,542	$ 19,635	$ 41,212