Accumulated Other Comprehensive Income (Loss) - Changes in components of AOCI - (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Accumulated Other Comprehensive Income (Loss)
Balance at the beginning of the period	$ (3,871)
Other comprehensive income (loss), net of tax	7,376	$ 3,375
Balance at the end of the period	3,505	2,998
Amortization of defined benefit pension
Accumulated Other Comprehensive Income (Loss)
Balance at the beginning of the period	(6,015)	(5,315)
Amounts reclassified from accumulated other comprehensive income (loss)	126	140
Other comprehensive income (loss), net of tax	126	140
Balance at the end of the period	(5,889)	(5,175)
Gain and Losses on sales of available for sale securities
Accumulated Other Comprehensive Income (Loss)
Balance at the beginning of the period	2,588	5,467
Other comprehensive income (loss) before reclassifications	7,375	3,263
Amounts reclassified from accumulated other comprehensive income (loss)	(76)
Other comprehensive income (loss), net of tax	7,299	3,263
Balance at the end of the period	9,887	8,730
Gains and Losses on Cash Flow Hedges
Accumulated Other Comprehensive Income (Loss)
Balance at the beginning of the period	(444)	(529)
Other comprehensive income (loss) before reclassifications	(94)	(75)
Amounts reclassified from accumulated other comprehensive income (loss)	45	47
Other comprehensive income (loss), net of tax	(49)	(28)
Balance at the end of the period	(493)	(557)
Accumulated Other Comprehensive Income (Loss).
Accumulated Other Comprehensive Income (Loss)
Balance at the beginning of the period	(3,871)	(377)
Other comprehensive income (loss) before reclassifications	7,281	3,188
Amounts reclassified from accumulated other comprehensive income (loss)	95	187
Other comprehensive income (loss), net of tax	7,376	3,375
Balance at the end of the period	$ 3,505	$ 2,998