Securities (Additional Information) (Details)	12 Months Ended
	Dec. 31, 2016 USD ($) security	Dec. 31, 2015 USD ($) security	Dec. 31, 2014 USD ($)
Schedule of Investments [Line Items]
Unrealized gains on securities available-for-sale included in accumulated other comprehensive income, net of deferred taxes	$ (6,085,000)	$ (3,801,000)
Unrealized gains on securities available-for-sale included in accumulated other comprehensive income, deferred taxes	$ 3,227,000	$ 2,047,000
Number of investment securities which had unrealized losses for twelve months or longer | security	209	109
AFS and HTM securities in Continues Unrealized Loss Position	$ 658,500,000	$ 546,000,000
AFS and HTM Securities Unrealized Loss Accumulated in Investments	13,200,000	10,200,000
Investment securities with unrealized losses for twelve months or longer	103,708,000	192,809,000
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	3,850,000	6,709,000
Investment securities with unrealized losses that are considered temporary	615,699,000	540,460,000
Available For Sale Securities Continuous Unrealized Loss Position Aggregate Losses Accumulated In Investments	(12,536,000)	(10,141,000)
Other than temporary impairment losses		0
Federal Home Loan Bank Stock	17,800,000	20,600,000
Federal Reserve Bank Stock	5,400,000	908,000
Carrying value of investments sold	28,800,000	12,400,000	$ 25,200,000
Security pledged as collateral, amortized cost	597,300,000	577,600,000
Security pledged as collateral, fair value	$ 589,700,000	$ 570,900,000
Unrealized Loss as a Percent of Amortized Cost	2.00%	2.00%
Gross realized gains	$ 125,000	$ 221,000	451,000
Mortgage Backed Securities and Collateralized Mortgage Obligations [Member]
Schedule of Investments [Line Items]
Investment securities with unrealized losses for twelve months or longer	103,700,000	192,800,000
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	3,900,000	6,700,000
Available-for-sale Securities [Member]
Schedule of Investments [Line Items]
Unrealized gains on securities available-for-sale included in accumulated other comprehensive income, deferred taxes	3,300,000	2,000,000
Gross realized gains	$ 51,000	$ 4,000	$ 451,000