Retained Earnings Restriction (Detail Textuals) - USD ($)	9 Months Ended
	Sep. 30, 2016	Dec. 31, 2015
Retained Earnings Restriction [Line Items]
Equity to total capitalization ratio	52.90%
Total Capitalization	$ 1,117,476,000	$ 1,048,869,000
OTP
Retained Earnings Restriction [Line Items]
Total Capitalization	$ 1,123,168,000
OTP | Minimum
Retained Earnings Restriction [Line Items]
Equity to total capitalization ratio	47.50%
OTP | Maximum
Retained Earnings Restriction [Line Items]
Equity to total capitalization ratio	58.10%