Condensed Financial Statements of Parent Company - Summary of Condensed Balance Sheets of Parent Company (Detail) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
ASSETS
Cash in subsidiary bank	$ 212,505	$ 62,135
Other assets	298,052	185,672
Total assets	11,520,717	9,833,425	$ 9,839,555
LIABILITIES AND SHAREHOLDERS’ EQUITY
Other borrowings	123,630	123,871
Total liabilities	10,467,922	8,876,609
Shareholders' equity	1,052,795	956,816	$ 920,964	$ 855,872
Total liabilities and shareholders’ equity	11,520,717	9,833,425
Customers Bancorp
ASSETS
Cash in subsidiary bank	62,643	16,684
Other assets	6,583	3,417
Total assets	1,249,798	1,081,490
LIABILITIES AND SHAREHOLDERS’ EQUITY
Other borrowings	195,670	123,871
Other liabilities	1,333	803
Total liabilities	197,003	124,674
Shareholders' equity	1,052,795	956,816
Total liabilities and shareholders’ equity	1,249,798	1,081,490
Bank Subsidiaries
ASSETS
Investments in and receivables due from bank subsidiary	1,178,166	1,059,671
Non-Bank Subsidiaries
ASSETS
Investments in and receivables due from bank subsidiary	$ 2,406	$ 1,718