Investment Securities (Details 1) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Unrealized Losses on Securities Available-for-Sale, Less than 12 Months, Fair Value	$ 546,888	$ 316,746
Unrealized Losses on Securities Available-for-Sale, Less than 12 Months, Gross Unrealized Losses	(1,570)	(2,032)
Unrealized Losses on Securities Available-for-Sale, 12 Months or Longer, Fair Value	2,683	1,706,835
Unrealized Losses on Securities Available-for-Sale, 12 Months or Longer, Gross Unrealized Losses	(18)	(38,258)
Unrealized Losses on Securities Available-for-Sale, Fair Value	549,571	2,023,581
Unrealized Losses on Securities Available-for-Sale, Gross Unrealized Losses	(1,588)	(40,290)
Government agency and government-sponsored enterprise pass through securities
Unrealized Losses on Securities Available-for-Sale, Less than 12 Months, Fair Value	0	60,164
Unrealized Losses on Securities Available-for-Sale, Less than 12 Months, Gross Unrealized Losses	0	(169)
Unrealized Losses on Securities Available-for-Sale, 12 Months or Longer, Fair Value	435	85,245
Unrealized Losses on Securities Available-for-Sale, 12 Months or Longer, Gross Unrealized Losses	(1)	(2,131)
Unrealized Losses on Securities Available-for-Sale, Fair Value	435	145,409
Unrealized Losses on Securities Available-for-Sale, Gross Unrealized Losses	(1)	(2,300)
Government agency and government-sponsored enterprise collateralized mortgage obligations
Unrealized Losses on Securities Available-for-Sale, Less than 12 Months, Fair Value	172,738	69,859
Unrealized Losses on Securities Available-for-Sale, Less than 12 Months, Gross Unrealized Losses	(389)	(326)
Unrealized Losses on Securities Available-for-Sale, 12 Months or Longer, Fair Value	2,127	164,097
Unrealized Losses on Securities Available-for-Sale, 12 Months or Longer, Gross Unrealized Losses	(15)	(5,046)
Unrealized Losses on Securities Available-for-Sale, Fair Value	174,865	233,956
Unrealized Losses on Securities Available-for-Sale, Gross Unrealized Losses	(404)	(5,372)
Private label collateralized mortgage obligations
Unrealized Losses on Securities Available-for-Sale, Less than 12 Months, Fair Value	0	32,170
Unrealized Losses on Securities Available-for-Sale, Less than 12 Months, Gross Unrealized Losses	0	(831)
Unrealized Losses on Securities Available-for-Sale, 12 Months or Longer, Fair Value	121	49,237
Unrealized Losses on Securities Available-for-Sale, 12 Months or Longer, Gross Unrealized Losses	(2)	(1,262)
Unrealized Losses on Securities Available-for-Sale, Fair Value	121	81,407
Unrealized Losses on Securities Available-for-Sale, Gross Unrealized Losses	(2)	(2,093)
Collateralized loan obligations
Unrealized Losses on Securities Available-for-Sale, Less than 12 Months, Fair Value	82,606
Unrealized Losses on Securities Available-for-Sale, Less than 12 Months, Gross Unrealized Losses	(298)
Unrealized Losses on Securities Available-for-Sale, 12 Months or Longer, Fair Value	0
Unrealized Losses on Securities Available-for-Sale, 12 Months or Longer, Gross Unrealized Losses	0
Unrealized Losses on Securities Available-for-Sale, Fair Value	82,606
Unrealized Losses on Securities Available-for-Sale, Gross Unrealized Losses	(298)
Municipal securities
Unrealized Losses on Securities Available-for-Sale, Less than 12 Months, Fair Value		52,386
Unrealized Losses on Securities Available-for-Sale, Less than 12 Months, Gross Unrealized Losses		(238)
Unrealized Losses on Securities Available-for-Sale, 12 Months or Longer, Fair Value		284,915
Unrealized Losses on Securities Available-for-Sale, 12 Months or Longer, Gross Unrealized Losses		(7,082)
Unrealized Losses on Securities Available-for-Sale, Fair Value		337,301
Unrealized Losses on Securities Available-for-Sale, Gross Unrealized Losses		(7,320)
Government agency and government-sponsored enterprise commercial mortgage-backed securities
Unrealized Losses on Securities Available-for-Sale, Less than 12 Months, Fair Value	176,063	40,641
Unrealized Losses on Securities Available-for-Sale, Less than 12 Months, Gross Unrealized Losses	(181)	(341)
Unrealized Losses on Securities Available-for-Sale, 12 Months or Longer, Fair Value	0	1,020,684
Unrealized Losses on Securities Available-for-Sale, 12 Months or Longer, Gross Unrealized Losses	0	(21,184)
Unrealized Losses on Securities Available-for-Sale, Fair Value	176,063	1,061,325
Unrealized Losses on Securities Available-for-Sale, Gross Unrealized Losses	(181)	(21,525)
US Treasury Securities
Unrealized Losses on Securities Available-for-Sale, Less than 12 Months, Fair Value		49,729
Unrealized Losses on Securities Available-for-Sale, Less than 12 Months, Gross Unrealized Losses		(88)
Unrealized Losses on Securities Available-for-Sale, 12 Months or Longer, Fair Value		0
Unrealized Losses on Securities Available-for-Sale, 12 Months or Longer, Gross Unrealized Losses		0
Unrealized Losses on Securities Available-for-Sale, Fair Value		49,729
Unrealized Losses on Securities Available-for-Sale, Gross Unrealized Losses		(88)
Asset-backed Securities
Unrealized Losses on Securities Available-for-Sale, Less than 12 Months, Fair Value	115,481	11,548
Unrealized Losses on Securities Available-for-Sale, Less than 12 Months, Gross Unrealized Losses	(702)	(38)
Unrealized Losses on Securities Available-for-Sale, 12 Months or Longer, Fair Value	0	35,859
Unrealized Losses on Securities Available-for-Sale, 12 Months or Longer, Gross Unrealized Losses	0	(443)
Unrealized Losses on Securities Available-for-Sale, Fair Value	115,481	47,407
Unrealized Losses on Securities Available-for-Sale, Gross Unrealized Losses	$ (702)	(481)
SBA asset-backed securities
Unrealized Losses on Securities Available-for-Sale, Less than 12 Months, Fair Value		249
Unrealized Losses on Securities Available-for-Sale, Less than 12 Months, Gross Unrealized Losses		(1)
Unrealized Losses on Securities Available-for-Sale, 12 Months or Longer, Fair Value		66,798
Unrealized Losses on Securities Available-for-Sale, 12 Months or Longer, Gross Unrealized Losses		(1,110)
Unrealized Losses on Securities Available-for-Sale, Fair Value		67,047
Unrealized Losses on Securities Available-for-Sale, Gross Unrealized Losses		$ (1,111)