Consolidated Statement of Changes in Equity (USD $) In Thousands, except Share data	Total	Common Stock	Additional Capital	Retained Earnings	Accumulated Other Comprehensive Income	Treasury Stock
Balance, at Dec. 31, 2013	$ 333,581	$ 5,173	$ 29,745	$ 297,515	$ 1,522	$ (374)
Shares Issued, Beginning Balance (in shares) at Dec. 31, 2013		5,173,450
Net income	15,244			15,244
Dividends paid	(16,607)			(16,607)
Change in unrealized net gain on available-for-sale securities	1,841				1,841
Change in value of interest rate cap	42				42
Balance, at Mar. 31, 2014	334,101	5,173	29,745	296,152	3,405	(374)
Shares Issued, Ending Balance (in shares) at Mar. 31, 2014		5,173,000
Balance, at Dec. 31, 2014	348,399	5,173	30,139	299,004	14,457	(374)
Shares Issued, Beginning Balance (in shares) at Dec. 31, 2014	5,173,450	5,173,000
Net income	17,822			17,822
Dividends paid	(17,890)			(17,890)
Change in unrealized net gain on available-for-sale securities	493				493
Change in value of interest rate cap	(6)				(6)
Balance, at Mar. 31, 2015	$ 348,818	$ 5,173	$ 30,139	$ 298,936	$ 14,944	$ (374)
Shares Issued, Ending Balance (in shares) at Mar. 31, 2015	5,173,450	5,173,450