Stockholders' Equity	9 Months Ended
Sep. 30, 2018
Equity [Abstract]
Stockholders' Equity	Stockholders' Equity Dividend and Stock Split On October 22, 2018, the Bancorp declared a $0.35 per share cash dividend, payable on November 8, 2018 to shareholders of record at the close of business on November 1, 2018. Additionally, Bancorp announced a 2:1 stock split, payable on November 27, 2018, to shareholders of record at the close of business on November 9, 2018. See Note 1, Basis of Presentation, for the pro forma effect of the stock split on reported earnings per share for the periods presented. Share-Based Payments The fair value of stock options as of the grant date is recorded as stock-based compensation expense in the consolidated statements of comprehensive income over the requisite service period, which is generally the vesting period, with a corresponding increase in common stock. Stock-based compensation also includes compensation expense related to the issuance of restricted stock awards. The fair value of the restricted stock awards on the grant date, which equals the intrinsic value, is recorded as compensation expense over the requisite service period with a corresponding increase in common stock as the shares vest. Stock option and restricted stock awards issued in 2018 include a retirement eligibility clause whereby the requisite service period is satisfied at the retirement eligibility date. For those awards, we accelerate stock-based compensation if the award holder is eligible to retire. However, retirement eligibility does not affect the legal vesting schedule of the awards. Performance-based stock awards (restricted stock awards) are issued to a selected group of employees. Stock award vesting is contingent upon the achievement of pre-established long-term performance goals set by the Compensation Committee of the Board of Directors. Performance is measured over a three-year period and the stock awards cliff vest. These performance-based stock awards were granted at a maximum opportunity level, and based on the achievement of the pre-established goals, the actual payouts can range from 0% to 200% of the target award. For performance-based stock awards, an estimate is made of the number of shares expected to vest based on the probability that the performance criteria will be achieved to determine the amount of compensation expense to be recognized. The estimate is re-evaluated quarterly and total compensation expense is adjusted for any change in the current period. In addition, we record excess tax benefits (deficiencies) resulting from the exercise of non-qualified stock options, the disqualifying disposition of incentive stock options and vesting of restricted stock awards as income tax benefits (expense) in the consolidated statements of comprehensive income with a corresponding decrease (increase) to current taxes payable. The holders of unvested restricted stock awards are entitled to dividends on the same per-share ratio as holders of common stock. Tax benefits on dividends paid on unvested restricted stock awards are recorded as tax benefits in the consolidated statements of comprehensive income with a corresponding decrease to current taxes payable. Under the 2017 Equity Plan, stock options may be net settled by a reduction in the number of shares otherwise deliverable upon exercise in satisfaction of the exercise payment and applicable tax withholding requirements. During the nine months ended September 30, 2018, option holders exchanged 20,981 shares totaling $1.5 million at a weighted-average price of $71.35 for cashless stock option exercises and tax withholdings upon vesting of performance-based stock awards. During the nine months ended September 30, 2017, option holders exchanged 11,938 shares totaling $782 thousand at a weighted-average price of $65.50 for cashless stock option exercises. Shares exchanged under net settlement arrangements are available for future grants under the 2017 Equity Plan. Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income We early adopted ASU No. 2018-02, Income Statement - Reporting Comprehensive Income (Topic 220): Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income, in the first quarter of 2018 and reclassified $638 thousand from AOCI to retained earnings. This amount represents the stranded income tax effects related to the unrealized loss on available-for-sale securities in AOCI on the date of the enactment of the Tax Cuts and Jobs Act of 2017. For more information regarding ASU No. 2018-02, refer to Note 2, Accounting Standards Adopted in 2018. Share Repurchase Program On April 23, 2018, Bancorp announced that its Board of Directors approved a Share Repurchase Program under which Bancorp may repurchase up to $25.0 million of its outstanding common stock through May 1, 2019. Under the Share Repurchase Program, Bancorp may purchase shares of its common stock through various means such as open market transactions, including block purchases, and privately negotiated transactions. The number of shares repurchased and the timing, manner, price and amount of any repurchases will be determined at Bancorp's discretion. Factors include, but are not limited to, stock price, trading volume and general market conditions, along with Bancorp’s general business conditions. The program may be suspended or discontinued at any time and does not obligate Bancorp to acquire any specific number of shares of its common stock. As part of the Share Repurchase Program, Bancorp entered into a trading plan adopted in accordance with Rule 10b5-1 of the Securities Exchange Act of 1934, as amended. The 10b5-1 trading plan permits common stock to be repurchased at times that might otherwise be prohibited under insider trading laws or self-imposed trading restrictions. The 10b5-1 trading plan is administered by an independent broker and is subject to price, market volume and timing restrictions. During the nine months ended September 30, 2018, Bancorp purchased 17,943 shares for a total amount of $1.5 million.

Stockholders' Equity

Dividend and Stock Split

On October 22, 2018, the Bancorp declared a $0.35 per share cash dividend, payable on November 8, 2018 to shareholders of record at the close of business on November 1, 2018. Additionally, Bancorp announced a 2:1 stock split, payable on November 27, 2018, to shareholders of record at the close of business on November 9, 2018. See Note 1, Basis of Presentation, for the pro forma effect of the stock split on reported earnings per share for the periods presented.

Share-Based Payments

The fair value of stock options as of the grant date is recorded as stock-based compensation expense in the consolidated statements of comprehensive income over the requisite service period, which is generally the vesting period, with a corresponding increase in common stock. Stock-based compensation also includes compensation expense related to the issuance of restricted stock awards. The fair value of the restricted stock awards on the grant date, which equals the intrinsic value, is recorded as compensation expense over the requisite service period with a corresponding increase in common stock as the shares vest. Stock option and restricted stock awards issued in 2018 include a retirement eligibility clause whereby the requisite service period is satisfied at the retirement eligibility date. For those awards, we accelerate stock-based compensation if the award holder is eligible to retire. However, retirement eligibility does not affect the legal vesting schedule of the awards.

Performance-based stock awards (restricted stock awards) are issued to a selected group of employees. Stock award vesting is contingent upon the achievement of pre-established long-term performance goals set by the Compensation Committee of the Board of Directors. Performance is measured over a three-year period and the stock awards cliff vest. These performance-based stock awards were granted at a maximum opportunity level, and based on the achievement of the pre-established goals, the actual payouts can range from 0% to 200% of the target award. For performance-based stock awards, an estimate is made of the number of shares expected to vest based on the probability that the performance criteria will be achieved to determine the amount of compensation expense to be recognized. The estimate is re-evaluated quarterly and total compensation expense is adjusted for any change in the current period.

In addition, we record excess tax benefits (deficiencies) resulting from the exercise of non-qualified stock options, the disqualifying disposition of incentive stock options and vesting of restricted stock awards as income tax benefits (expense) in the consolidated statements of comprehensive income with a corresponding decrease (increase) to current taxes payable.

The holders of unvested restricted stock awards are entitled to dividends on the same per-share ratio as holders of common stock. Tax benefits on dividends paid on unvested restricted stock awards are recorded as tax benefits in the consolidated statements of comprehensive income with a corresponding decrease to current taxes payable.

Under the 2017 Equity Plan, stock options may be net settled by a reduction in the number of shares otherwise deliverable upon exercise in satisfaction of the exercise payment and applicable tax withholding requirements. During the nine months ended September 30, 2018, option holders exchanged 20,981 shares totaling $1.5 million at a weighted-average price of $71.35 for cashless stock option exercises and tax withholdings upon vesting of performance-based stock awards. During the nine months ended September 30, 2017, option holders exchanged 11,938 shares totaling $782 thousand at a weighted-average price of $65.50 for cashless stock option exercises. Shares exchanged under net settlement arrangements are available for future grants under the 2017 Equity Plan.

Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income

We early adopted ASU No. 2018-02, Income Statement - Reporting Comprehensive Income (Topic 220): Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income, in the first quarter of 2018 and reclassified $638 thousand from AOCI to retained earnings. This amount represents the stranded income tax effects related to the unrealized loss on available-for-sale securities in AOCI on the date of the enactment of the Tax Cuts and Jobs Act of 2017. For more information regarding ASU No. 2018-02, refer to Note 2, Accounting Standards Adopted in 2018.

Share Repurchase Program

On April 23, 2018, Bancorp announced that its Board of Directors approved a Share Repurchase Program under which Bancorp may repurchase up to $25.0 million of its outstanding common stock through May 1, 2019.

Under the Share Repurchase Program, Bancorp may purchase shares of its common stock through various means such as open market transactions, including block purchases, and privately negotiated transactions. The number of shares repurchased and the timing, manner, price and amount of any repurchases will be determined at Bancorp's discretion. Factors include, but are not limited to, stock price, trading volume and general market conditions, along with Bancorp’s general business conditions. The program may be suspended or discontinued at any time and does not obligate Bancorp to acquire any specific number of shares of its common stock.

As part of the Share Repurchase Program, Bancorp entered into a trading plan adopted in accordance with Rule 10b5-1 of the Securities Exchange Act of 1934, as amended. The 10b5-1 trading plan permits common stock to be repurchased at times that might otherwise be prohibited under insider trading laws or self-imposed trading restrictions. The 10b5-1 trading plan is administered by an independent broker and is subject to price, market volume and timing restrictions.

During the nine months ended September 30, 2018, Bancorp purchased 17,943 shares for a total amount of $1.5 million.