Stockholders' Equity - Summary of Repurchases During the Period (Details) - USD ($)								1 Months Ended																																	3 Months Ended	12 Months Ended
	Jun. 30, 2015	Jan. 01, 2015	Jun. 13, 2014	Jan. 20, 2014	Jan. 01, 2014	Mar. 14, 2013	Jan. 01, 2013	Dec. 31, 2015	Nov. 30, 2015	Oct. 31, 2015	Sep. 30, 2015	Aug. 31, 2015	Jul. 31, 2015	Jun. 30, 2015	May. 31, 2015	Apr. 30, 2015	Mar. 31, 2015	Feb. 28, 2015	Jan. 31, 2015	Dec. 31, 2014	Nov. 30, 2014	Oct. 31, 2014	Jun. 30, 2014	May. 31, 2014	Apr. 30, 2014	Mar. 31, 2014	Feb. 28, 2014	Jan. 30, 2014	Dec. 31, 2013	Nov. 30, 2013	Oct. 31, 2013	Sep. 30, 2013	Aug. 31, 2013	Jul. 31, 2013	Jun. 30, 2013	May. 31, 2013	Apr. 30, 2013	Mar. 31, 2013	Feb. 28, 2013	Jan. 31, 2013	Sep. 30, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Jun. 29, 2015
Equity [Abstract]
Total Number of Shares Purchased	0	0	0	0	0	0	0	118,746	199,391	211,040	129,849	0	0	160,000	200,000	203,820	100,000	0	0	84,634	30,000	0	51,760	139,568	185,000	40,000	0	0	0	0	167,675	10,000	0	0	0	60,000	2,164	150,587	0	3,638	0	1,322,846		394,064
Average Price Paid per Share (in dollars per share)	$ 0.00	$ 0.00	$ 0.00	$ 0.00	$ 0.00	$ 0.00	$ 0.00	$ 22.39	$ 22.11	$ 23.19	$ 23.15	$ 0.00	$ 0.00	$ 24.93	$ 25.59	$ 30.84	$ 31.69	$ 0.00	$ 0.00	$ 34.09	$ 35.48	$ 0.00	$ 34.95	$ 35.11	$ 34.60	$ 35.26	$ 0.00	$ 0.00	$ 0.00	$ 0.00	$ 36.86	$ 37.91	$ 0.00	$ 0.00	$ 0.00	$ 32.55	$ 33.00	$ 32.30	$ 0.00	$ 34.79	$ 0.00	$ 25.34	$ 34.78	$ 34.47
Total Number of Shares Purchased as Part of Publicly Announced Plans or Programs	0	0	0	0	0	3,638	0	118,746	199,391	211,040	129,849	0	0	160,000	200,000	203,820	100,000	0	0	84,634	30,000	0	51,760	139,568	185,000	40,000	0	0	394,064	394,064	394,064	226,389	216,389	216,389	216,389	216,389	156,389	154,225	3,638	3,638	0	1,322,846	530,962	394,064
Maximum Number of Shares that May Yet Be Purchased Under the Plans or Programs	0	0	0	147,284	0	0	0	0	0	0	0	0	0	0	0	0	66,910	116,910	116,910	0	84,634	114,634	0	0	14,784	107,284	147,284	147,284	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0
Maximum Number (or Approximate Dollar Value) of Shares that May Yet Be Purchased Under the Plans or Programs	$ 15,114,029	$ 15,027,043	$ 15,027,043	$ 9,417,721	$ 9,417,721	$ 22,866,068	$ 7,992,647	$ 148,008	$ 2,806,575	$ 7,214,395	$ 12,107,835	$ 15,114,029	$ 15,114,029	$ 15,114,029	$ 4,102,131	$ 9,220,841	$ 13,442,543	$ 15,027,043	$ 15,027,043	$ 15,027,043	$ 15,027,043	$ 15,027,043	$ 27,043	$ 1,836,055	$ 6,217,221	$ 9,417,721	$ 9,417,721	$ 9,417,721	$ 9,417,721	$ 9,417,721	$ 9,417,721	$ 15,598,221	$ 15,977,321	$ 15,977,321	$ 15,977,321	$ 15,977,321	$ 17,930,337	$ 18,001,740	$ 7,866,068	$ 7,866,068	$ 15,027,043	$ 148,008	$ 15,027,043	$ 9,417,721	$ 114,029