Fair Value Measurements - Schedule of Fair Value of Derivative Instruments and Loans Held for Sale (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Derivative notional amount and balance sheet location
Assumed Gain on Sale	$ 29,575	$ 25,091
Total Fair Value Adjustment	29,575	25,091
Derivative assets	11,678	14,535
Derivative Liabilities	(1,333)	(4,877)
Fair Value Adjustment To Loans Held for Sale	19,231	15,433
Loans Held for Sale
Derivative notional amount and balance sheet location
Notional or Principal Amount	2,479,880	1,056,683
Assumed Gain on Sale	20,108	13,812
Interest Rate Movement Effect	(877)	1,621
Total Fair Value Adjustment	19,231	15,433
Fair Value Adjustment To Loans Held for Sale	19,231	15,433
Rate Lock Commitments
Derivative notional amount and balance sheet location
Notional or Principal Amount	267,710	472,558
Assumed Gain on Sale	9,467	11,279
Interest Rate Movement Effect	(1,494)	273
Total Fair Value Adjustment	7,973	11,552
Derivative assets	7,973	11,552
Forward Sale Contracts
Derivative notional amount and balance sheet location
Notional or Principal Amount	2,747,590	1,529,241
Interest Rate Movement Effect	2,371	(1,894)
Total Fair Value Adjustment	2,371	(1,894)
Derivative assets	3,705	2,983
Derivative Liabilities	$ (1,333)	$ (4,877)