Regulatory Matters - Summary of Capital Amounts, Tier 1 Risk Based and Tier 1 Leveraged Ratios (Detail) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Tier 1 capital (to risk-weighted assets), for capital adequacy purposes ratio	6.00%
Tier 1 capital (to risk-weighted assets), to be well capitalized under prompt corrective action provisions ratio	8.00%
Customers Bancorp, Inc.
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Common equity Tier 1 (to risk-weighted-assets), actual amount	$ 500,624
Total capital (to risk-weighted assets), actual amount	698,323	$ 578,644
Tier 1 capital (to risk-weighted assets), actual amount	556,193	437,712
Tier 1 capital (to average assets), actual amount	$ 556,193	$ 437,712
Common equity Tier 1 (to risk-weighted assets), actual ratio	7.61%
Total capital (to risk-weighted assets), actual ratio	10.62%	11.09%
Tier 1 capital (to risk-weighted assets), actual ratio	8.46%	8.39%
Tier 1 capital (to average assets), actual ratio	7.16%	6.69%
Common equity Tier 1 (to risk-weighted assets), for capital adequacy purposes amount	$ 296,014
Total capital (to risk-weighted assets), for capital adequacy purposes amount	526,247	$ 417,473
Tier 1 capital (to risk-weighted assets), for capital adequacy purposes amount	394,685	208,737
Tier 1 capital (to average assets), for capital adequacy purposes amount	$ 310,812	$ 261,622
Common equity Tier 1 (to risk-weighted assets), for capital adequacy purposes ratio	4.50%
Total capital (to risk-weighted assets), for capital adequacy purposes ratio	8.00%	8.00%
Tier 1 capital (to risk-weighted assets), for capital adequacy purposes ratio	6.00%	4.00%
Tier 1 capital (to average assets), for capital adequacy purposes ratio	4.00%	4.00%
Customers Bank
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Common equity Tier 1 (to risk-weighted-assets), actual amount	$ 565,217
Total capital (to risk-weighted assets), actual amount	710,864	$ 621,894
Tier 1 capital (to risk-weighted assets), actual amount	565,217	480,963
Tier 1 capital (to average assets), actual amount	$ 565,217	$ 480,963
Common equity Tier 1 (to risk-weighted assets), actual ratio	8.62%
Total capital (to risk-weighted assets), actual ratio	10.85%	11.98%
Tier 1 capital (to risk-weighted assets), actual ratio	8.62%	9.27%
Tier 1 capital (to average assets), actual ratio	7.30%	7.39%
Common equity Tier 1 (to risk-weighted assets), for capital adequacy purposes amount	$ 294,916
Total capital (to risk-weighted assets), for capital adequacy purposes amount	524,295	$ 415,141
Tier 1 capital (to risk-weighted assets), for capital adequacy purposes amount	393,221	207,570
Tier 1 capital (to average assets), for capital adequacy purposes amount	$ 309,883	$ 260,462
Common equity Tier 1 (to risk-weighted assets), for capital adequacy purposes ratio	4.50%
Total capital (to risk-weighted assets), for capital adequacy purposes ratio	8.00%	8.00%
Tier 1 capital (to risk-weighted assets), for capital adequacy purposes ratio	6.00%	4.00%
Tier 1 capital (to average assets), for capital adequacy purposes ratio	4.00%	4.00%
Common equity Tier 1 (to risk-weighted assets), to be well capitalized under prompt correction action provisions amount	$ 425,990
Total capital (to risk-weighted assets), to be well capitalized under prompt corrective action provisions amount	655,369	$ 518,926
Tier 1 capital (to risk-weighted assets), to be well capitalized under prompt corrective action provisions amount	524,295	311,356
Tier 1 capital (to average assets), to be well capitalized under prompt corrective action provisions amount	$ 387,353	$ 325,577
Common equity Tier 1 (to risk-weighted assets), to be well capitalized under prompt corrective action provisions ratio	6.50%
Total capital (to risk-weighted assets), to be well capitalized under prompt corrective action provisions ratio	10.00%	10.00%
Tier 1 capital (to risk-weighted assets), to be well capitalized under prompt corrective action provisions ratio	8.00%	6.00%
Tier 1 capital (to average assets), to be well capitalized under prompt corrective action provisions ratio	5.00%	5.00%