Nature of Operations and Basis of Presentation - Accumulated Other Comprehensive Income (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Accounting Policies [Abstract]
Net unrealized securities gains/(losses), pretax	$ (4,885)	$ (23,443)	$ 6,032
Accumulated Other Comprehensive Income (Loss), Cumulative Changes in Net Gain (Loss) from Cash Flow Hedges, Effect Before Tax	(525)	0	0
Pension, other postretirement and postemployement benefit plan adjustments, pretax	(6,696)	(5,068)	(6,566)
Accumulated other comprehensive loss, pretax	(12,106)	(28,511)	(534)
Net unrealized securities gains/(losses), after-tax	(3,017)	(14,476)	3,650
Interest rate swaps, net of tax	(324)	0	0
Pension, other postretirement and postemployement benefit plan adjustments, after-tax	(4,134)	(3,129)	(3,973)
Accumulated other comprehensive loss, after-tax	$ (7,475)	$ (17,605)	$ (323)