Shareholders' Equity	3 Months Ended
Shareholders' Equity	Mar. 31, 2020
Equity [Abstract]
Shareholders' Equity	Shareholders' Equity Share Repurchases Effective January 1, 2020, the Company's board of directors authorized the repurchase of up to $150.0 million in common shares through December 31, 2021. During the three months ended March 31, 2020, the Company repurchased 128,865 shares at an average price of $71.58 per share for an aggregate purchase price of $9.2 million related to this authorization. At March 31, 2020, the Company had $140.8 million remaining under this authorization. Effective September 30, 2017, the Company's board of directors authorized the repurchase of up to $150.0 million in common shares, which expired on September 30, 2019. During the three months ended March 31, 2019, the Company repurchased 501 shares at an average price of $64.80 per share related to this authorization. The Company also purchases shares of common stock from restricted stock award recipients upon the award vesting or as recipients sell shares to meet their employment tax obligations. The Company purchased 94,615 shares and 563,284 shares, or $8.1 million and $39.7 million of the Company's common stock for these purposes during the three months ended March 31, 2020 and 2019, respectively. Issuance of Shares The Company issues common shares out of treasury stock as a result of employee restricted share vesting and exercise transactions as discussed in Note 17. During the three months ended March 31, 2020 and 2019, the Company issued 254,111 shares and 1,035,360 shares, respectively, related to these obligations. During the three months ended March 31, 2020, the Company also issued 34,205 common shares out of treasury stock for Sandler O'Neill deal consideration, as discussed in Note 3. Dividends The Company's current dividend policy includes both a quarterly and an annual special cash dividend. The annual special cash dividend is payable in the first quarter of each year, with the intention of returning a metric based on the Company's net income from the previous fiscal year. During the three months ended March 31, 2020, the Company declared and paid both a quarterly and annual special cash dividend on its common stock of $0.375 and $0.75 per share, respectively, totaling $16.1 million. On May 1, 2020, the board of directors declared a cash dividend of $0.20 per share to be paid on June 12, 2020, to shareholders of record as of the close of business on May 29, 2020. Noncontrolling Interests The consolidated financial statements include the accounts of Piper Sandler Companies, its wholly owned subsidiaries and other entities in which the Company has a controlling financial interest. Noncontrolling interests represent equity interests in consolidated entities that are not attributable, either directly or indirectly, to Piper Sandler Companies. Noncontrolling interests primarily represent the minority equity holders' proportionate share of the equity in the Company's merchant banking funds. Ownership interests in entities held by parties other than the Company's common shareholders are presented as noncontrolling interests within shareholders' equity, separate from the Company's own equity. Revenues, expenses and net income or loss are reported on the consolidated statements of operations on a consolidated basis, which includes amounts attributable to both the Company's common shareholders and noncontrolling interests. Net income or loss is then allocated between the Company and noncontrolling interests based upon their relative ownership interests. Net income applicable to noncontrolling interests is deducted from consolidated net income to determine net income applicable to the Company. There was no other comprehensive income or loss attributed to noncontrolling interests for the three months ended March 31, 2020 and 2019.