Parent Company Only Financial Statements - Schedule of Consolidated Statements of Cash Flows (Details) - USD ($) $ in Thousands	3 Months Ended									12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Cash Flows From Operating Activities:
Net income (loss)	$ 635	$ 402	$ 699	$ 941	$ (2,864)	$ (2,865)	$ (3,209)	$ 1,124	$ 563	$ 2,677	$ (4,387)	$ 1,425
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Charitable foundation contribution expense											6,093
Deferred income taxes										(184)	(40)	126
Share-based compensation expense										98
Net decrease (increase) in accrued interest receivable										(460)	(628)	(39)
Increase in other assets										(371)	38	175
Net increase in other liabilities										2,390	3,313	893
Net cash provided by operating activities										7,885	8,646	4,343
Cash Flows From Investing Activities:
Net cash used in investing activities										(126,608)	(135,898)	(43,893)
Cash Flows From Financing Activities:
Proceeds from issuance of common stock											78,191
Funds loaned to the ESOP											(7,238)
Net cash provided by financing activities										128,777	175,260	38,572
Net increase (decrease) in cash and cash equivalents										10,054	48,008	$ (978)
Cash and cash equivalents at beginning of year				59,724						59,724
Cash and cash equivalents at end of year	69,778				59,724	59,724				69,778	59,724
Ponce Bank Mutual Holding Company
Cash Flows From Operating Activities:
Net income (loss)										2,677	(4,387)
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Equity in undistributed earnings of subsidiaries										(4,400)	(566)
Charitable foundation contribution expense											6,093
Deferred income taxes										83	(1,261)
Share-based compensation expense										98
Increase in other assets										(257)	(88)
Net increase in other liabilities										202	62
Net cash provided by operating activities										(1,597)	(147)
Cash Flows From Investing Activities:
Investment in Ponce Bank											(39,272)
Repayment of ESOP Loan										404	526
Net cash used in investing activities										404	(38,746)
Cash Flows From Financing Activities:
Proceeds from issuance of common stock											78,191
Funds loaned to the ESOP											(7,238)
Net cash provided by financing activities											70,953
Net increase (decrease) in cash and cash equivalents										(1,193)	32,060
Cash and cash equivalents at beginning of year				$ 32,060						32,060
Cash and cash equivalents at end of year	$ 30,867				$ 32,060	$ 32,060				$ 30,867	$ 32,060