Capital Requirements - Dividends to Parent (Details) - USD ($)	3 Months Ended	9 Months Ended
	Jun. 30, 2017	Sep. 30, 2017	Dec. 31, 2016
Cash dividend
Retained earnings		$ 63,679,000	$ 52,527,000
HCC (Parent)
Cash dividend
Cash dividend available		21,260,000
Dividends paid to parent company	$ 4,000,000	12,000,000
Retained earnings		$ 24,051,000