Fair Value Measurements - Schedule of Fair Value of Derivative Instruments and Loans Held for Sale (Detail) - USD ($) $ in Thousands	6 Months Ended	12 Months Ended
	Jun. 30, 2016	Dec. 31, 2015
Derivative notional amount and balance sheet location
Assumed Gain on Sale	$ 60,796	$ 29,575
Interest Rate Movement Effect	914
Total Fair Value Adjustment	61,710	29,575
Derivative assets	28,358	11,678
Derivative Liabilities	(29,483)	(1,333)
Fair Value Adjustment To Loans Held for Sale	62,835	19,231
Loans Held for Sale
Derivative notional amount and balance sheet location
Notional or Principal Amount	2,181,494	2,479,880
Assumed Gain on Sale	41,652	20,108
Interest Rate Movement Effect	21,183	(877)
Total Fair Value Adjustment	62,835	19,231
Fair Value Adjustment To Loans Held for Sale	62,835	19,231
Rate Lock Commitments
Derivative notional amount and balance sheet location
Notional or Principal Amount	627,317	267,710
Assumed Gain on Sale	19,144	9,467
Interest Rate Movement Effect	8,725	(1,494)
Total Fair Value Adjustment	27,869	7,973
Derivative assets	27,869	7,973
Forward Sale Contracts
Derivative notional amount and balance sheet location
Notional or Principal Amount	2,761,496	2,747,590
Interest Rate Movement Effect	(27,269)	2,371
Total Fair Value Adjustment	(27,269)	2,371
Derivative assets	489	3,705
Derivative Liabilities	(27,758)	$ (1,333)
Interest Rate Swaps
Derivative notional amount and balance sheet location
Notional or Principal Amount	34,460
Interest Rate Movement Effect	(1,725)
Total Fair Value Adjustment	(1,725)
Derivative Liabilities	$ (1,725)