Stockholders' Equity	12 Months Ended
Dec. 31, 2017
Stockholders' Equity Disclosure [Abstract]
Stockholders' Equity	NOTE 17. STOCKHOLDERS' EQUITY Common Stock Repurchased The Company's common stock repurchased consisted of: (1) restricted stock surrendered as treasury shares and (2) stock purchased under the Company's Stock Repurchase Program and retired. Treasury Shares As a Delaware corporation, the Company records treasury shares for shares surrendered to the Company resulting from statutory payroll tax obligations arising from the vesting of restricted stock. During the years ended December 31, 2017, 2016, and 2015, the Company purchased 188,870 treasury shares at a weighted average price of $50.17 per share, 141,358 treasury shares at a weighted average price of $37.59 per share, and 180,822 treasury shares at a weighted average price of $46.46 per share. Stock Repurchase Program The Stock Repurchase Program was initially authorized by PacWest's Board of Directors on October 17, 2016, pursuant to which the Company could, until December 31, 2017, purchase shares of its common stock for an aggregate purchase price not to exceed $400 million. On November 15, 2017, PacWest's Board of Directors amended the Stock Repurchase Program to reduce the authorized purchase amount to $150 million and extend the maturity date to December 31, 2018. On February 14, 2018, PacWest's Board of Directors amended the Stock Repurchase Program to increase the authorized purchase amount to $350 million and extend the maturity date to February 28, 2019. The common stock repurchases may be effected through open market purchases or in privately negotiated transactions and may utilize any derivative or similar instrument to effect share repurchase transactions (including, without limitation, accelerated share repurchase contracts, equity forward transactions, equity option transactions, equity swap transactions, cap transactions, collar transactions, floor transactions or other similar transactions or any combination of the foregoing transactions). The amount and exact timing of any repurchases will depend upon market conditions and other factors. The Stock Repurchase Program may be suspended or discontinued at any time. During the year ended December 31, 2017, the Company repurchased 2,081,227 shares for $99.7 million at a weighted average price of $47.89 per share. During the year ended December 31, 2016, the Company repurchased 652,835 shares for $27.9 million at a weighted average price of $42.78 per share. All shares repurchased under the Stock Repurchase Program were retired upon settlement. At December 31, 2017, the remaining amount that could be used to repurchase shares under the Stock Repurchase Program was $112.5 million. After the amendment on February 14, 2018, the remaining amount that could be used to repurchase shares under the Stock Repurchase Program is $350 million.

NOTE 17. STOCKHOLDERS' EQUITY

Common Stock Repurchased

The Company's common stock repurchased consisted of: (1) restricted stock surrendered as treasury shares and (2) stock purchased under the Company's Stock Repurchase Program and retired.

Treasury Shares

As a Delaware corporation, the Company records treasury shares for shares surrendered to the Company resulting from statutory payroll tax obligations arising from the vesting of restricted stock. During the years ended December 31, 2017, 2016, and 2015, the Company purchased 188,870 treasury shares at a weighted average price of $50.17 per share, 141,358 treasury shares at a weighted average price of $37.59 per share, and 180,822 treasury shares at a weighted average price of $46.46 per share.

Stock Repurchase Program

The Stock Repurchase Program was initially authorized by PacWest's Board of Directors on October 17, 2016, pursuant to which the Company could, until December 31, 2017, purchase shares of its common stock for an aggregate purchase price not to exceed $400 million. On November 15, 2017, PacWest's Board of Directors amended the Stock Repurchase Program to reduce the authorized purchase amount to $150 million and extend the maturity date to December 31, 2018. On February 14, 2018, PacWest's Board of Directors amended the Stock Repurchase Program to increase the authorized purchase amount to $350 million and extend the maturity date to February 28, 2019.

The common stock repurchases may be effected through open market purchases or in privately negotiated transactions and may utilize any derivative or similar instrument to effect share repurchase transactions (including, without limitation, accelerated share repurchase contracts, equity forward transactions, equity option transactions, equity swap transactions, cap transactions, collar transactions, floor transactions or other similar transactions or any combination of the foregoing transactions).

The amount and exact timing of any repurchases will depend upon market conditions and other factors. The Stock Repurchase Program may be suspended or discontinued at any time. During the year ended December 31, 2017, the Company repurchased 2,081,227 shares for $99.7 million at a weighted average price of $47.89 per share. During the year ended December 31, 2016, the Company repurchased 652,835 shares for $27.9 million at a weighted average price of $42.78 per share. All shares repurchased under the Stock Repurchase Program were retired upon settlement. At December 31, 2017, the remaining amount that could be used to repurchase shares under the Stock Repurchase Program was $112.5 million. After the amendment on February 14, 2018, the remaining amount that could be used to repurchase shares under the Stock Repurchase Program is $350 million.