Fair Value - Fair Value Measurement (Detail) $ in Thousands	6 Months Ended
	Jun. 30, 2017 USD ($)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assumed Gain/(Loss) From Loan Sale	$ (3,642)
Interest Rate Movement Effect	(2,660)
Servicing Rights Value	8,870
Security Price Change	2,977
Total Fair Value Measurement Gain/(Loss)	5,545
Mortgage Banking [Member] | Level 2 [Member] | Fair Value, Measurements, Recurring [Member] | Rate Lock Commitments [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Notional or Principal Amount	655,409
Assumed Gain/(Loss) From Loan Sale	(2,645)
Interest Rate Movement Effect	(2,111)
Servicing Rights Value	6,267
Total Fair Value Measurement Gain/(Loss)	1,511
Mortgage Banking [Member] | Level 2 [Member] | Fair Value, Measurements, Recurring [Member] | Forward Sales Contracts [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Notional or Principal Amount	777,148
Security Price Change	2,977
Total Fair Value Measurement Gain/(Loss)	2,977
Mortgage Banking [Member] | Level 2 [Member] | Fair Value, Measurements, Recurring [Member] | Mortgages Held for Sale [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Notional or Principal Amount	240,341
Assumed Gain/(Loss) From Loan Sale	(997)
Interest Rate Movement Effect	(549)
Servicing Rights Value	2,603
Total Fair Value Measurement Gain/(Loss)	$ 1,057