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Carrying value as of the balance sheet date of dividends declared but unpaid on equity securities issued by the entity and outstanding.

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Period which shares may be purchased under a stock repurchase plan authorized by an entity's Board of Directors, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Shareholders' Equity (Additional Information) (Details) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2019 USD ($) $ / shares shares	Dec. 31, 2018 USD ($) $ / shares shares	Jan. 31, 2020 shares	Jan. 31, 2019 shares	Dec. 31, 2017 USD ($)	Oct. 08, 2015 USD ($)	Sep. 24, 2013 shares
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
number of years	2
Dividends declared to shareholders \| $	$ 18,900	$ 18,000			$ 14,600
Stock repurchased during period, shares	488,052	750
Stockholders' Equity Note, Stock Split, Conversion Ratio	1.5
Subordinated Debt \| $	$ 59,080	$ 59,067				$ 15,000
Value Of Trust Preferred Securities Included In Tier 1 Capital \| $	$ 43,000	43,000				$ 43,000
Subordinated Debt, Phase-Out Period, Annual, Percentage	0.2
Subordinated Debt, Phase-Out Period	6 years
Subsidiaries [Member]
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Dividends declared to shareholders \| $	$ 36,900	$ 28,100			$ 16,800
2013 Common Stock Repurchase Program [Member]
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Stock repurchase program, shares of common stock approved for repurchase							375,000
Stock repurchased during period, shares		750
Shares repurchased, average cost per share \| $ / shares		$ 26.57
Share Repurchase Program Three [Member]
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Stock repurchase program, shares of common stock approved for repurchase				775,000
Stock repurchased during period, shares	488,052
Shares repurchased, average cost per share \| $ / shares	$ 42.61
Share Repurchase Program Four [Member]
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Stock Repurchase Program, Period in Force	12 months
Tier II Capital [Domain]
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Subordinated Debt \| $	$ 15,000	$ 15,000
Subsequent Event [Member] \| Share Repurchase Program Four [Member]
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Stock repurchase program, shares of common stock approved for repurchase			750,000