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Amount after adjustments of available-for-sale debt securities at cost, maturing after the tenth fiscal year following the latest fiscal year. Adjustments include, but are not limited to, accretion, amortization, collection of cash, previous other-than-temporary impairments (OTTI) recognized in earnings less cumulative-effect adjustments, and fair value hedge accounting adjustments. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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Amount after adjustments of available-for-sale debt securities at cost, maturing in the next fiscal year following the latest fiscal year. Adjustments include, but are not limited to, accretion, amortization, collection of cash, previous other-than-temporary impairments (OTTI) recognized in earnings less cumulative-effect adjustments, and fair value hedge accounting adjustments. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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Securities - Amortized Cost and Fair Value of Securities by Contractual Maturity (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017	Mar. 31, 2017
Amortized Cost
Due within one year	$ 28,692
Due after one year through five years	67,311
Due after five years through ten years	78,917
Due after ten years	72,703
Amortized Cost	961,589	$ 674,104	$ 2,496
Fair Value
Due within one year	29,028
Due after one year through five years	68,747
Due after five years through ten years	79,724
Due after ten years	71,335
Fair Value	948,365	671,488
Other debt securities
Amortized Cost
Amortized Cost	23,994	17,106
Other debt securities, amortized cost	15,163
Fair Value
Other debt securities, fair value	15,021
Fair Value	23,940	17,290
Government agency mortgage backed securities \| Residential mortgage-backed securities
Amortized Cost
Amortized Cost	416,954	196,121
Fair Value
Fair Value	409,470	193,950
Government agency mortgage backed securities \| Commercial mortgage-backed securities
Amortized Cost
Amortized Cost	27,636	31,015
Fair Value
Fair Value	27,502	31,170
Government agency collateralized mortgage obligations \| Residential mortgage-backed securities
Amortized Cost
Amortized Cost	244,213	180,258
Fair Value
Fair Value	237,666	176,639
Government agency collateralized mortgage obligations \| Commercial mortgage-backed securities
Amortized Cost
Amortized Cost	10,000	5,019
Fair Value
Fair Value	$ 9,872	$ 5,006