Piper Jaffray Companies (Parent Company only) - Condensed Statements of Financial Condition (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Assets
Cash and cash equivalents	$ 41,359	$ 189,910	$ 15,867	$ 123,683
Other assets	164,962	117,665
Total assets	2,125,503	2,138,518
Liabilities and Shareholders’ Equity
Senior notes	175,000	175,000
Accrued compensation	288,255	251,638
Other liabilities and accrued expenses	42,553	62,901
Total liabilities	1,309,237	1,305,698
Total common shareholders’ equity	759,250	783,659
Total liabilities and shareholders’ equity	2,125,503	2,138,518
Parent Company
Assets
Cash and cash equivalents	1,170	48	$ 200	$ 336
Investment in and advances to subsidiaries	941,215	982,426
Other assets	22,031	15,843
Total assets	964,416	998,317
Liabilities and Shareholders’ Equity
Senior notes	175,000	175,000
Accrued compensation	27,756	36,347
Other liabilities and accrued expenses	2,410	3,311
Total liabilities	205,166	214,658
Total common shareholders’ equity	759,250	783,659
Total liabilities and shareholders’ equity	$ 964,416	$ 998,317