Subsequent Events	3 Months Ended
Mar. 31, 2017
Subsequent Events [Abstract]
Subsequent Events	SUBSEQUENT EVENTS CU Bancorp Merger Announcement On April 6, 2017, PacWest announced the signing of a definitive agreement and plan of merger (the "Agreement") whereby PacWest will acquire CU Bancorp in a transaction valued at approximately $705 million. CU Bancorp, headquartered in Los Angeles, California, is the parent of California United Bank, a California state-chartered non-member bank, with approximately $3.0 billion in assets and nine branches located in Los Angeles, Orange, Ventura, and San Bernardino counties at December 31, 2016. In connection with the transaction, California United Bank will be merged into Pacific Western Bank, the principal operating subsidiary of PacWest Bancorp. The transaction, which was approved by the PacWest and CU Bancorp boards of directors, is expected to close in the fourth quarter of 2017 and is subject to customary closing conditions, including obtaining approval by CU Bancorp’s shareholders and bank regulatory authorities. As of December 31, 2016, on a pro forma consolidated basis, the combined company would have approximately $25.0 billion in assets and 87 branches, prior to contemplated consolidations. Under terms of the Agreement, CU Bancorp shareholders will receive 0.5308 shares of PacWest common stock and $12.00 in cash for each share of CU Bancorp. Based on PacWest’s April 5, 2017 closing price of $51.72, the total value of the merger consideration is $39.45 per CU Bancorp share. Common Stock Dividends On May 1, 2017, the Company announced that the Board of Directors had declared a quarterly cash dividend of $0.50 per common share. The cash dividend is payable on May 31, 2017 to stockholders of record at the close of business on May 22, 2017. We have evaluated events that have occurred subsequent to March 31, 2017 and have concluded there are no other subsequent events that would require recognition in the accompanying consolidated financial statements.

SUBSEQUENT EVENTS

CU Bancorp Merger Announcement

On April 6, 2017, PacWest announced the signing of a definitive agreement and plan of merger (the "Agreement") whereby PacWest will acquire CU Bancorp in a transaction valued at approximately $705 million.

CU Bancorp, headquartered in Los Angeles, California, is the parent of California United Bank, a California state-chartered non-member bank, with approximately $3.0 billion in assets and nine branches located in Los Angeles, Orange, Ventura, and San Bernardino counties at December 31, 2016. In connection with the transaction, California United Bank will be merged into Pacific Western Bank, the principal operating subsidiary of PacWest Bancorp.

The transaction, which was approved by the PacWest and CU Bancorp boards of directors, is expected to close in the fourth quarter of 2017 and is subject to customary closing conditions, including obtaining approval by CU Bancorp’s shareholders and bank regulatory authorities.

As of December 31, 2016, on a pro forma consolidated basis, the combined company would have approximately $25.0 billion in assets and 87 branches, prior to contemplated consolidations.

Under terms of the Agreement, CU Bancorp shareholders will receive 0.5308 shares of PacWest common stock and $12.00 in cash for each share of CU Bancorp. Based on PacWest’s April 5, 2017 closing price of $51.72, the total value of the merger consideration is $39.45 per CU Bancorp share.

Common Stock Dividends

On May 1, 2017, the Company announced that the Board of Directors had declared a quarterly cash dividend of $0.50 per common share. The cash dividend is payable on May 31, 2017 to stockholders of record at the close of business on May 22, 2017.

We have evaluated events that have occurred subsequent to March 31, 2017 and have concluded there are no other subsequent events that would require recognition in the accompanying consolidated financial statements.