CONSOLIDATED STATEMENTS OF STOCKHOLDER'S EQUITY (USD $) In Thousands, except Share data	Total	Common Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]
Beginning Balance at Dec. 31, 2011	$ 247,587	$ 2	$ 131,612	$ 115,973
Beginning Balance, shares at Dec. 31, 2011		22,108,233
Net income	26,984			26,984
Issuance of common stock under the Equity Plan	724		724
Issuance of common stock under the Equity Plan, shares		51,319
Issuance of common stock for vested restricted stock units under the Equity Plan, shares		258,730
Purchased and retired common stock and other	(283)	0	(283)
Purchased and retired common stock and other, shares		(21,657)
Amortization of stock based compensation	1,224		1,224
Cash distributions declared	(16,752)			(16,752)
Common stock repurchase program	(8,065)	0	(8,065)
Common stock repurchase program, shares		(712,173)
Issuance of restricted common stock under the Equity Plan, shares		16,901
Ending Balance at Dec. 31, 2012	251,419	2	125,212	126,205
Ending Balance, shares at Dec. 31, 2012		21,701,353
Net income	27,530			27,530
Issuance of common stock under the Equity Plan	539		539
Issuance of common stock under the Equity Plan, shares		41,702
Purchased and retired common stock and other	(1,532)	0	(1,532)
Purchased and retired common stock and other, shares		(108,459)
Amortization of stock based compensation	3,045		3,045	0
Cash distributions declared	(11,051)			(11,051)
Issuance of restricted common stock under the Equity Plan, shares		17,745
Ending Balance at Dec. 31, 2013	269,950	2	127,264	142,684
Ending Balance, shares at Dec. 31, 2013		21,652,341
Net income	20,745			20,745
Issuance of common stock under the Equity Plan	85		85
Issuance of common stock under the Equity Plan, shares		5,820
Issuance of common stock for vested restricted stock units under the Equity Plan, shares		559,689
Purchased and retired common stock and other	(99)	0	(99)
Purchased and retired common stock and other, shares		0
Amortization of stock based compensation	3,753		3,753
Cash distributions declared	(11,050)			(11,050)
Common stock repurchase program	(4,325)	0	(4,325)
Common stock repurchase program, shares		(263,772)
Issuance of restricted common stock under the Equity Plan, shares		24,684
Ending Balance at Dec. 31, 2014	$ 279,059	$ 2	$ 126,678	$ 152,379
Ending Balance, shares at Dec. 31, 2014		21,978,762