Accumulated Other Comprehensive Income (Loss) - Schedule of Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Accumulated Other Comprehensive Income Loss [Line Items]
Balance	$ 1,359,056	$ 1,080,498	$ 1,054,208
Net change	(23,879)	18,744	(39,571)
Balance	1,438,274	1,359,056	1,080,498
Unrealized Gains (Losses) on Securities Available for Sale
Accumulated Other Comprehensive Income Loss [Line Items]
Balance	(2,160)	(21,819)	5,901
Net change	(22,119)	21,605	(27,720)
Reclassification of amounts within AOCI to retained earnings due to tax reform		(1,946)
Balance	(24,279)	(2,160)	(21,819)
Unrealized Gains (Losses) on Defined Benefit Pension Plans
Accumulated Other Comprehensive Income Loss [Line Items]
Balance	(531)	(500)	(487)
Net change	203	121	(13)
Reclassification of amounts within AOCI to retained earnings due to tax reform		(152)
Balance	(328)	(531)	(500)
Unrealized Gains (Losses) on Derivative Instruments Designated as Cash Flow Hedges
Accumulated Other Comprehensive Income Loss [Line Items]
Balance	(16,342)	(10,212)	1,626
Net change	(1,963)	(2,982)	(11,838)
Reclassification of amounts within AOCI to retained earnings due to tax reform		(3,148)
Balance	(18,305)	(16,342)	(10,212)
Accumulated OCI
Accumulated Other Comprehensive Income Loss [Line Items]
Balance	(19,033)	(32,531)	7,040
Net change	(23,879)	18,744	(39,571)
Reclassification of amounts within AOCI to retained earnings due to tax reform		(5,246)
Balance	$ (42,912)	$ (19,033)	$ (32,531)