Retained Earnings Restriction (Detail Textuals) - USD ($)	3 Months Ended
	Mar. 31, 2016	Dec. 31, 2015
Retained Earnings Restriction [Line Items]
Total Capitalization	$ 1,107,521,000	$ 1,048,869,000
OTP
Retained Earnings Restriction [Line Items]
Equity to total capitalization ratio	52.00%
OTP | Minimum
Retained Earnings Restriction [Line Items]
Equity to total capitalization ratio	46.90%
OTP | Maximum
Retained Earnings Restriction [Line Items]
Equity to total capitalization ratio	57.30%
Total Capitalization	$ 1,056,300,000