Investment Securities - Contractual Maturity (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Amortized Cost
Due in one year or less	$ 29,832
Due after one year through five years	101,697
Total contractual maturities	131,529
Amortized Cost	4,080,663	$ 4,640,419
Fair Value
Due in one year or less	29,888
Due after one year through five years	101,439
Total contractual maturities	131,327
Fair value	4,075,644	4,498,342
Mortgage-backed securities:
Amortized Cost
Government debt securities, mortgaged-backed securities and obligations	786,968
Fair Value
Government debt securities, mortgaged-backed securities and collateralized mortgage obligations	792,420
Residential - Government agency
Amortized Cost
Government debt securities, mortgaged-backed securities and obligations	290,131
Amortized Cost	290,131	426,710
Fair Value
Government debt securities, mortgaged-backed securities and collateralized mortgage obligations	291,209
Fair value	291,209	411,536
Residential - Government-sponsored enterprises
Amortized Cost
Government debt securities, mortgaged-backed securities and obligations	395,039
Amortized Cost	395,039	156,056
Fair Value
Government debt securities, mortgaged-backed securities and collateralized mortgage obligations	399,492
Fair value	399,492	150,847
Commercial - Government-sponsored enterprises
Amortized Cost
Government debt securities, mortgaged-backed securities and obligations	101,798
Amortized Cost	101,798
Fair Value
Government debt securities, mortgaged-backed securities and collateralized mortgage obligations	101,719
Fair value	101,719
Collateralized mortgage obligations
Amortized Cost
Government debt securities, mortgaged-backed securities and obligations	3,162,166
Fair Value
Government debt securities, mortgaged-backed securities and collateralized mortgage obligations	3,151,897
Government agency
Amortized Cost
Government debt securities, mortgaged-backed securities and obligations	2,390,143
Amortized Cost	2,390,143	2,779,620
Fair Value
Government debt securities, mortgaged-backed securities and collateralized mortgage obligations	2,381,278
Fair value	2,381,278	2,682,449
Government-sponsored enterprises
Amortized Cost
Government debt securities, mortgaged-backed securities and obligations	772,023
Amortized Cost	772,023	620,337
Fair Value
Government debt securities, mortgaged-backed securities and collateralized mortgage obligations	770,619
Fair value	$ 770,619	$ 602,592

Amortized cost of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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