Equity - Capital Requirements (Details) - USD ($)	Sep. 30, 2019	Dec. 31, 2018
Equity [Abstract]
Capital required for capital adequacy	$ 608,400,000	$ 545,000,000.0
Capital	793,300,000	727,600,000
Excess capital	$ 184,900,000	$ 182,600,000

The amount of total capital as defined in the regulations.

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