Fair Value Measurement: (Tables)

3 Months Ended

Mar. 31, 2015

Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]

Fair Value, Assets Measured on Recurring and Nonrecurring Basis [Table Text Block]

	Fair value measurements at March 31, 2015 using
	Total carrying value		Quoted prices in active markets for identical assets (level 1)		Significant other observable inputs (level 2)		Significant unobservable inputs (level 3)
Available for sale securities	$	46,254	$	3,484	$	42,770	$	—
	$	46,254	$	3,484	$	42,770	$	—

	Fair value measurements at December 31, 2014 using
	Total carrying value		Quoted prices in active markets for identical assets (level 1)		Significant other observable inputs (level 2)		Significant unobservable inputs (level 3)
Available for sale securities	$	70,952	$	5,884	$	65,068	$	—
	$	70,952	$	5,884	$	65,068	$	—