Goodwill and Other Intangible Assets - Summary of Core Deposit Intangibles, Customer Renewal Lists and Mortgage Servicing Rights (Detail) - USD ($) $ in Thousands |
Dec. 31, 2015 |
Dec. 31, 2014 |
---|---|---|
Finite-Lived Intangible Assets [Line Items] | ||
Gross carrying amount | $ 136,711 | $ 131,254 |
Accumulated amortization | (91,067) | (83,750) |
Core deposit intangibles, Total | 45,644 | 47,504 |
Core Deposit Intangibles [Member] | ||
Finite-Lived Intangible Assets [Line Items] | ||
Gross carrying amount | 111,594 | 108,593 |
Accumulated amortization | (79,362) | (71,818) |
Core deposit intangibles, Total | 32,232 | 36,775 |
Customer Renewal Lists [Member] | ||
Finite-Lived Intangible Assets [Line Items] | ||
Gross carrying amount | 12,351 | 10,970 |
Accumulated amortization | (7,860) | (7,099) |
Core deposit intangibles, Total | 4,491 | 3,871 |
Mortgage Servicing Rights [Member] | ||
Finite-Lived Intangible Assets [Line Items] | ||
Gross carrying amount | 12,766 | 11,691 |
Accumulated amortization | (3,845) | (4,833) |
Core deposit intangibles, Total | $ 8,921 | $ 6,858 |